A trope most prevalent in Western Animation, but it can occur elsewhere. An actor is often cast into a role for which they can provide a great voice, but not always do the casting agents manage to get someone that can sing as well. A second actor will be brought in to dub the songs, and this isn't always as noticeable as one might think.
If the actor is supposed to be playing a musical instrument while singing, two doubles may well be used.
Most Japanese voice artists sing the Image Song for their characters regardless of their talent, although again this isn't always the case.
Less frequently, concessions will be made to work around a voice actor with a less than pleasant voice.
Compare Talent Double and Singing Voice Dissonance.
Completely averted with Brock in the 4Kids dub. Of course, Eric Stuart is a musician as well as a voice actor.
In the English dub of Gundam SEED and Gundam SEED Destiny, Lacus Clyne is voiced by two different actresses when speaking normally and when singing - it's pretty obvious in SEED, but much less so in Destiny. In original Japanese, Rie Tanaka performs both, though.
French dub simply… didn't dub the songs, so Lacus has Rie Tanaka's voice when she sings.
The Macross franchise tends to have different singing and speaking voices for the singer characters. Exceptions are Iijima Mari (Lynn Minmay) and Nakajima Megumi (Ranka Lee).
In the Robotech adaptation, Rebecca Forstadt did her own singing. Some fans thought it was okay, but she clearly lacked Iijima's professional music talent.
Yellow Belmont in Genesis Climber MOSPEADA had different voice actors for not only speaking and singing roles, but also gender roles. For Yellow's female Idol Singer persona, Mine Matsuki performed both speaking and singing voices, while Hirotaka Suzuoki was Yellow's normal male speaking voice.
A third seiyuu was brought in for the OVA sequel Love Live Alive, as Jin Haneoka performed as Yellow's male singing voice.
In the Robotech adaptation, Yellow, or "Lancer," was once again voiced by two different voice actors: Cam Clarke for speaking roles and Michael Bradley for singing. Unlike the original series, both actors were male, although Clarke did make a rather unconvincing attempt at an effeminate voice.
Priss in Bubblegum Crisis Tokyo 2040 also had a different person doing her singing, although that wasn't the case in the original OVA.
Averted in the English dub, where Christine Auten did both the speaking and the singing voices for Priss. However, Sinda Nichols did not do her own singing for the original OVA, where Priss's songs were covered by various artists.
Normally averted by Japanese seiyuu, but for Saiyuki's Hakkai it's played straight. One can only imagine how terrible his singing voice is, as his Image Song is spoken-word. He's left out of the group song entirely. Lampshaded by Minekura when she referred to the other three seiyuu as "-8" ("Minus Eight"), with Hakkai's name being written with the kanji for "eight."
Akira Ishida's singing voice doesn't seem to be as bad as he thinks it is (it's not good, but at least it's on key). Still, he refuses to sing if he has to do any image songs.
He did sing in the two collaborations between the Saiyuki and Weiß Kreuz casts, though. Apparently, that was too much Fanservice to pass up.
Another anime where this happens is for Koyuki's singing in BECK. It's painfully obvious, too. Funnily enough, the dub averts this, as Greg Ayres does his own singing.
In yet another anime exception, the theme song from Excel♥Saga is sung by Excel and Hyatt— but not their normal speaking voice actors. This being Excel Saga, it is lampshaded in one episode where Excel and Hyatt meet their singing voice actors, in full Excel and Hyatt cosplay, at a bowling alley:
They did the opening because they had already made an album under the name Excel Girls wearing the said cosplay.
Subverted in Hidamari Sketch where the characters (and voice actresses) visit a karaoke parlor and sing nothing like they have for the openings/imagesongs, but rather sing more like how their characters would.
Subverted in Haruhi-chan. Yuki talks as she usually does through the whole opening theme while everyone else sings, looking like the "work-around voice actor with less than pleasant voice" variation. Then came the end of episode 6, where she suddenly pulls out a karaoke mic and starts singing "Paradise Lost" to get Achakura to forget the argument they just had.
Meanwhile, Lucky Star left all the songs to the Japanese cast. The rapidfire switching off between Wendee Lee speaking and Aya Hirano singing was a bit distracting.
In the English version of episode 14 of Slayers Next, Lina (voiced by Lisa Ortiz) shouted "In Japanese!" before she and Amelia started to sing, using the original Japanese audio track. It did somewhat fit, since the song Lina and Amelia were supposed to be singing was Meme and Nene's "Lost Festival Dance". Meme and Nene were clearly Asian-themed characters.
We do get to hear Lisa and Veronica sing as a practice run though. While they don't sound good together (though it somewhat fit the situation, as it was supposed to be embarrassing), Crispin Freeman is on key when Zelgadis teaches them the embarrassing lyrics.
Averted with Ruika in the Slayers Premium short film, where Kira Vincent-Davis did her own singing.
A similar Lampshade Hanging came in the dub of Gokudo-kun Mannyuki: before several characters sing for a concert their de facto manager tells them "and remember to sing in Japanese!"
Phoron's singing voice in the Shinkyoku Soukai Polyphonica series is clearly not his own, since it's quite a bit higher than his usual speaking voice. Hiroshi Kamiya, Phoron's voice actor, does do his own singing for Phoron's image songs, but the voice he uses to contract Corti isn't his.
For the three North American dub CDs released of Sailor Moon, most of the show's voice actresses don't sing their characters' image songs. Jennifer Cihi sings Serena's, songwriter Shandi Sinnamon does Amy's, Sandy Howell does Raye's vocals, and Patricia Tollett does Lita's.
In the Love Hina dub, during episode 11 and episode 18 when the characters sing, the show switches back to the Japanese vocal track. However, the song in the Spring Special is dubbed by the English V As.
Averted in the FUNimation dub of One Piece, where the English voice actors sang the character song "Family" during a scene in Skypeia.
Ranma ½: Angela Costain did not do her own singing for Nabiki Tendo. Saffron Henderson sung for her instead. All the other voice actors did their own singing, notably Cathy Weseluck as Shampoo.
Annoyingly done in Full Moon o Sagashite where none of the English voice actors did any singing, and all of it was left in Japanese. It was pretty jarring, since the English voices sounded nothing like the Japanese. It doesn't help that the anime is all about singing.
Averted in Tenchi Muyo!, where most of the voice actors do most/all of their own singing, most notably Sherry Lynn (Kiyone #1/Sasami), Ellen Gerstell (Mihoshi #1), and Rebecca Forstadt (Mihoshi #2).
One exception is Petrea Burchard, who only sung as Ryoko in a karaoke scene where it didn't matter how good she was. Burchard admits that she can't sing, so when she was asked to sing "Up Walk in Galaxy" (the ending to Tenchi Universe), she tried to say no, but the producers insisted that she try, believing that she actually could sing some since she was a capable vocal actress. Burchard hesitantly agreed to give it a shot, and she was given the song and told to practice. She did, but when it came time to recording, she nervously made the entire production staff sit as far back in the room as they could. They started recording, and the staff let Burchard get about half-way through the song before they finally believed that she couldn't sing. Diane Michelle ended up singing the final song.
Michelle also sang Your Hiroshi in the Magical Girl Pretty Sammy OVAs as Chihiro Kawaii instead of either of her speaking voice actors Ellen Gerstell or Rebecca Forstadt (who ironically were both singers and did some singing for the franchise).
Aikatsu uses an idol unit specially made for the show to provide the girls' singing voices, even though there are some singers (such as Minako Kotobuki and Tomoya Kurosawa, who performs the opening to DokiDoki! Precure) among them. Justified that songs in the first season are lifted straight from the arcade game of the same name which appeared earlier. Also, Naoto is voiced by Toshiyuki Toyonaga, but the singing is done by Kenta Harada, the vocalist of Rey.
In Dr. No, Honey Ryder had the speaking voice of Monica Van der Zyl (who also did the Same Language Dub of many early Bond Girls), the singing voice of Diana Coupland and the body of Ursula Andress.
Zac Efron's singing lines in High School Musical are all sung by Drew Seeley, with Efron lip-synching. Apparently, it's pretty well done, but you can tell if you know it's there. This is because the vocal range of Troy was written for a tenor, and Zac, being a baritone, couldn't sing that high. The two sequels eventually changed Troy's vocal range to fit Zac's range better.
His natural singing voice can be heard in the first movie when Troy shows up at Gabriella's bedroom door.
Marni Nixon was the live-action queen of this for ages (often uncredited). From The Other Wiki: Nixon's dubbing career includes:
Providing Marilyn Monroe with a few top notes in her performance of "Diamonds Are a Girl's Best Friend" in Gentlemen Prefer Blondes (1953)
The singing voice for Deborah Kerr in two different movies - The King and I (1956), where her vocals were skilfully intertwined with Deborah's on some tracks; and An Affair to Remember a year later.
The singing voice for Natalie Wood as Maria in West Side Story (1961) and also sang some parts of the score of Anita played by Rita Moreno, sharing the load with co-dubber Betty Wand and Moreno herself. In parts of the quintet setting of the song "Tonight", Nixon sings both Maria's and Anita's lines.
Interestingly, there is a clip of Natalie Wood singing (in an untrained voice) "Tonight" mash-up with Nixon's dub (http://www.youtube.com/watch?v=n26hnzcT7SU). Wood had been trying to do her own singing and reportedly felt betrayed when she found out she was being dubbed.
The singing voice for Audrey Hepburn as Eliza in My Fair Lady (1964), for which Nixon gained much notoriety, as news-eager journalists ripped apart the customary veil of secrecy. Industry buzz has said this to have been the cause of Hepburn's failing even to get nominated for an Academy Award for the demanding role.
Interestingly, the DVD features the original footage of Hepburn singing, and while she's not as skilled as Nixon, she certainly doesn't embarrass herself. They probably could have gotten away with just letting her sing the part.
Nixon did get a moment on film, as Sister Sophia in The Sound of Music. Apparently everyone was worried about her meeting Julie Andrews (Nixon had dubbed Audrey Hepburn in My Fair Lady in the role that Andrews played on Broadway), but Andrews walked up to Nixon, shook her hand and said, "Marni, I'm such a big fan of yours!" Ice broken.
As mentioned below, Nixon was also June Foray's singing voice as Grandmother Fa in the animated Mulan.
Drew Barrymore was the only cast member who was dubbed in Woody Allen's musical Everyone Says I Love You, simply because she claimed she can't sing (though her performance in Music and Lyrics seems to go against this. Then again, 50 First Dates does back her up...). Oddly enough, several of her castmates, such as Edward Norton, were instructed to sing less well because their voices were considered too good to fit in with Allen's vision of normal people breaking into spontaneous musical numbers.
All the singing voices in Carmen Jones were dubbed in, even though the cast featured trained singers such as Harry Belafonte and Diahann Carroll.
In Joyeux Noël, set during the Christmas truce of World War I, German soldier Nikolaus Sprink (Benno Fürmann) and his lover Anna Sørensen (Diane Kruger) are both opera singers, and during their performance scenes, the singing voices of Natalie Dessay and Rolando Villazón are dubbed in.
Of the four leads in the 1958 film version of South Pacific, only Mitzi Gaynor got to use her own singing voice. Giorgio Tozzi, the bass who sang for Rossano Brazzi, is a name well known to opera buffs.
In White Christmas, Vera-Ellen's singing voice was provided by one Trudy Stevens. For the duet song "Sisters," Rosemary Clooney sang both parts (for herself and Vera).
Most other movie musicals featuring Vera-Ellen had someone else do her singing voice; On the Town assigned her a mostly non-singing part. It's pretty well known that while Vera-Ellen was an amazing dancer, singing was something she simply could not do. Ironically, her White Christmas costar, Rosemary Clooney, a great singer, admitted that her dancing wasn't exactly her specialty.
In Back to the Future, Mark Campbell was the one to sing "Johnny B. Goode" - in the place of Michael J. Fox. The song was credited as having been "performed by Marty McFly". (Fox does, however, do his own singing in Light Of Day).
In The Sound of Music, Christopher Plummer recorded every vocal to every song in the movie. In post-production he reviewed his tapes, decided that there was no way in hell he was good enough to sing opposite Julie Andrews, and gave permission for Bill Lee to dub him.
Kurt's high note in "So Long, Farewell" is actually sung by Liesl's little sister, Darleen Carr. According to Charmian's memoir Forever Liesl, Darleen and a few other children were hired to provide additional voices on the group numbers. All seven actors do sing every number, though. The only time additional voices are not used is the listless rendition of My Favorite Things at the beginning of Act II, just before Maria's voice joins theirs.
Margery MacKay provided the singing voice of Peggy Wood, who wasn't up to "Climb Every Mountain."
In the film version of The Phantom of the Opera, Margaret Preece sung Carlotta's songs instead of Minnie Driver (who did sing "Learn To Be Lonely" over the credits, but didn't have the operatic voice Carlotta needs). Preece also cameos as the female member of the trio in the "Il Muto" scene.
Rita Hayworth sang in many movies, but never in her own voice. To name only a few singers who dubbed for her:
Nan Wynn in You Were Never Lovelier. (Hayworth also conspicuously doesn't sing in the other movie musical pairing her with Fred Astaire, You'll Never Get Rich.)
Martha Mears in Cover Girl. (Mears also dubbed Veronica Lake's singing in several movies.)
Anita Ellis in Gilda. (Ellis also dubbed Vera-Ellen's singing in Three Little Words and The Belle of New York.)
Jo Ann Greer in Pal Joey (which also had Trudy Erwin as Kim Novak's singing voice).
Oh, that voice is so divine! I'm sorry it isn't mine.
Averted in the movie version of Guys and Dolls, where the tone-deaf Marlon Brando - even he admitted he was no singer - was given a singing voice by the miracle of sound editing. (It's ironic that he played a singing lead part, given that the musical's second male role, Nathan Detroit, was originally played by the tone-deaf Sam Levene and written to suit. In the movie, Nathan was played by Frank Sinatra.)
The same thing was done for Gloria Grahame as Ado Annie in the 1955 film version of Oklahoma!.
Most every film role that Lucille Ball did before television. After becoming a TV star, she used her own not-quite-singing voice for Mame (and the unsuccessful Broadway musical Wildcat which she starred in and co-produced).
In Gigi, Leslie Caron's singing was all dubbed by Betty Wand except for the verse of "The Night They Invented Champagne."
In John Waters' 1990 film Cry-Baby, all of the characters' singing voices were done by professional singers, including Rachel Sweet, who did Allison's (played by Amy Locane) singing. Johnny Depp, who is a musician, did not sing in this film.
In The Harvey Girls, Marion Doenges sang for Cyd Charisse and Virginia Rees sang for Angela Lansbury. That Lansbury didn't get to sing for herself is astounding in light of her later success in Broadway musicals in playing Mame and Mrs. Lovett.
Charisse was usually dubbed in other MGM musicals if required to sing. She didn't sing in Singin' in the Rain, but India Adams sang for her in The Band Wagon and Carole Richards was her singing voice in Brigadoon and Silk Stockings. Eileen Wilson did Charisse's singing in Words and Music.
In Bugsy Malone all the singing is done by adults with the kids lip-syncing. As a result it's glaringly obvious in places.
In Sister Act Wendy Makkena's character Sister Mary Robert's singing voice (the shy but cute nun) was dubbed by Andrea Robinson.
A weird case in Dark City. In the theatrical cut, nightclub singer Anna Murdoch is played by Jennifer Connelly, but her singing voice is provided by Anita Kelsey (who's also heard on the soundtrack album). In the director's cut, Jennifer Connelly does her own singing.
Singin' in the Rain: Debbie Reynolds had her singing voice dubbed over when her character, "Kathy," dubs "Lina" - Jean Hagen (Lina) for the speaking bits, and Betty Noyes for the songs "Would You" and "You Are My Lucky Star".
In The Mask, the song that Cameron Diaz's character sings is actually dubbed over by Susan Boyd.
In Moulin Rouge!, Jim Broadbent's singing voice in the operatic numbers is dubbed in by Anthony Weigh; however, this trope is averted for the two leads, who both sang their own parts.
Averted in the 1986 version of Little Shop of Horrors. Everyone does their own singing, with widely varying results (particularly note the "Suddenly Seymour" duets between Audrey, played by Ellen Greene - who in additional to being a professional singer also played the role in the original off-Broadway production and in the West End - and Seymour, played by Rick Moranis.)
Duets: Director Bruce Paltrow chose the actors cast in the primary roles of this film for their surprisingly good singing - with the exception of Scott Speedman, who averts this trope by playing the only main character who never sings a note. (Gwyneth Paltrow had two hit singles in Australia and New Zealand with songs from the film.) However, in the case of Ricky Kane (played by Andre Braugher), the in-story angelic nature of the character's voice forced the director to dub in a professional singer for his karaoke scenes.
In Gypsy, Rosalind Russell's singing was dubbed over by Lisa Kirk. Natalie Wood, however, got to use her own singing voice this time.
Gold Diggers of 1933 had Joan Blondell's singing dubbed over by Marian Anderson in "Remember My Forgotten Man." Blondell used her own singing voice in Dames. It was not pretty.
The film version of Oliver! had the vocals of the title character (played by Mark Lester) sung by Kathe Green, who was the daughter of the musical director.
In The Great Race, Natalie Wood's singing was once again dubbed, this time by Jackie Ward.
Only when she was singing "The Sweetheart Tree". During an earlier scene, she sings "My Country Tis Of Thee", and it is noticeably off-key.
Jackie Ward dubbed Natalie Wood’s singing again in Inside Daisy Clover, though you do get to hear a bit of Wood’s own singing voice on the intro to “You’re Gonna Hear From Me.”
In Paint Your Wagon, Jean Seberg's singing was dubbed by Anita Gordon. Clint Eastwood and Lee Marvin's singing voices infamously weren't dubbed. (This didn't keep Marvin from enjoying a UK #1 with "Wand'rin' Star.")
Parodied in Robin Hood: Men in Tights, where the singing voices sound nothing like the speaking voices (notably Arthur Rubin dubbing Cary Elwes).
Ava Gardner's singing was dubbed by Eileen Wilson in The Hucksters (1947), One Touch of Venus (1948) and The Bribe (1949). She was determined to put her vocal training to the test as Julie in the 1951 remake of Show Boat; Annette Warren's singing voice was nevertheless dubbed over hers, but Gardner did her own singing on the soundtrack album and in other movies of the 1950s.
Susan Kiger didn't sing "Shine Your Love" in the '70s flick Angels Revenge; the singing was actually dubbed by someone named Patty Foley.
Except for Bobby Van and (bizarrely) Sally Kellerman, the entire cast of the disastrous 1974 musical version of Lost Horizon was dubbed.
Averted in The Hunger Games; "Deep In The Meadow" (the lullaby Katniss sings to Prim and later to the fatally injured Rue) really is sung by Jennifer Lawrence (and Willow Shields, who plays Prim).
In Starstruck, Sterling Knight sings only the film's theme, all of his other songs are dubbed.
The film version of Lil Abner had the singing voice of Leslie Parrish (not from the original Broadway cast, unlike other principal actors) dubbed by Imogene Lynn.
In Gremlins Howie Mandell voiced Gizmo the mogwai, however his singing was done by an unidentified 14 year old girl who was part of the choir for the film.
Live Action TV
In The Partridge Family, only David Cassidy and Shirley Jones actually sang. The others all lip synched to session singers.
One Monty Python's Flying Circus sketch features John Cleese as an archaeologist who randomly bursts into song. Cleese by his own admission is a terrible singer (he did sing "Eric the Half a Bee," but very little else), so his singing parts in the sketch were dubbed in by Terry Jones.
In his pre-Python TV and radio shows Cleese sang "Rhubarb Tart" and "The Ferret Song", which must be heard to be believed.
Averted with Buffy, whose songs were originally going to be dubbed (supposedly by Jewel), but Sarah Michelle Gellar decided she didn't want to be the only one not doing her own vocals.
Similary in the Musical Episode of Scrubs, Elliot only has only a few sung lines throughout the episode, even during her and JD's friendship song, due to Sarah Chalke's apparent inability to sing. This inability to sing is later worked into Elliot's character as a running gag in Season 8.
Dawn Wells, who played Mary Ann in Gilligan's Island, couldn't even sing "For He's a Jolly Good Fellow" along with the rest of the cast without ruining it, and couldn't sing a single note without being dubbed over.
Her natural singing voice is used in one episode however, when Mary Ann believes that she's Ginger. IIRC it's what causes her to remember who she actually is, because the actual Ginger sings much better.
In "The Bitter Suite," the first Musical Episode of Xena: Warrior Princess, Renee O'Connor and Hudson Leick (Gabrielle and Callisto) sang with the respective voices of Susan Wood and Michelle Nicastro; Miss O'Connor subverted this in the second one ("Lyre Lyre, Hearts On Fire"), as she did sing here - along with Miss Wood and Susan Calloway!
Averted with Lucy Lawless (Xena) and Ted Raimi (Joxer) in both episodes, along with Kevin Smith (Ares) in the first one and Jay La Ga'ia (Draco) in the second.
The early nineties TV movie Freeze Frame dubbed its male lead (Kids Incorporated alum Ryan Lambert) in order to save money.
In Jeff Wayne's Rock Opera adaptation of The War of the Worlds, Sir Richard Burton is the narrating voice of the Journalist, whereas Justin Hayward is the character's singing voice.
Also applies visually in the stage version, where they are portrayed as a floating head on screen and a live actor on stage, respectively.
Inverted by the Gorillaz: 2D was originally played by real-life singer Damon Albarn, but had a second voice actor, (Nelson de Freitas,) hired to record his speaking voice.
Milli Vanilli was an extremely popular, award-winning rap/pop group in the late 80s and early 90s that returned a Grammy after it was revealed that the people getting all the credit for the music were just models dancing and lipsynching to uncredited vocalists. They were the original Trope Namer for the acting version.
They're just the most (in)famous example; several dance-oriented pop groups rely on attractive stand-ins lipsynching to others' voices.
Probably the second most famous case after Milli Vanilli was the story of Martha Wash. A very talented but rather large woman, she recorded vocals for several famous songs in the early Nineties, mostly for dance groups such as Black Box and C+C Music Factory (That famous "EVERYBODY DANCE NOW!" at the beginning of "Gonna Make You Sweat?" That was her). Unfortunately, someone decided that because of her size, she was unmarketable, and was replaced by a model lip-synching the song in the video, without her knowledge or her permission. She took the record label to court, demanding proper credit and royalties, and there is now a mandate that all performers are given proper credit on recordings.
Belgian house band One-Man Band Technotronic recorded their hit debut album Pump Up The Jam: The Album with rappers Ya Kid K and MC Eric providing vocals in the studio, but used Congolese supermodel Felly to lip-sync Ya Kid K's rapping in the music video to the hit title track. A small controversy ensued, and Ya Kid K was featured in the band's followup videos.
The Hamish And Dougal episode "Fame Idol", which hinges on Mrs Naughtie (played by Alison Steadman) having a beautiful singing voice (played by Jane Gilchrist). The series running on Rule of Funny, there was inevitably one scene where Mrs Naughtie sang in her own voice, for no reason whatsoever.
Averted with Rosie from Valkyria Chronicles, who has her singing voice provided by the main actresses in both English and Japanese. Hedy "Yuna" Burress stands up pretty damn well with her Japanese counterpart, a rare achievement.
Played straight with Hedy in Final Fantasy X-2, where the two main songs (real Emotion and 1000 Words) were sung by Jade Villalon. Though prior to this Koda Kumi sung both tracks in English, however, her pronunciation made the songs difficult to understand resulting in replacing. And if it counts, Hedy does a little "La la laa" while in Songstress mode.
In Loco Roco, yellow and green one both have different voice actors - one for singing, other for talking.
In Ape Escape 3, Pink Monkey is voiced by Debi Derryberry (speaking voice), and Anndi McAfee (singing voice).
Possibly justified in-universe: Inon Zur's orchestra starts playing to accompany her, and based on her remarks afterwards, that's not what she actually sounded like, but the way she remembered "In Uthenera" being performed.
While averted in the Japanese versions of the Ar tonelico series, the English versions fall squarely into this - because they use the same song, not even dubbed or covered.
Similar to the above example, in Tales of the Abyss Tear's (Nicole Karrer) fonic hymns are treated as sound effects, and use the original audio (Yukana).
Averted in The Elder Scrolls V: Skyrim, which is somewhat unfortunate because not all the voice actors who play bards can sing very well.
In Lunar: The Silver Star, Luna's English voice actress was Rhonda Gibson in the Working Designs era and Kathryn Kirk more recently, but Jenny Stigile provides Luna's singing voice in all the remakes.
Bruce Isaac's singing voice in Fallout: New Vegas is done by the project director and lead designer, Joshua Sawyer.
The "Powered by the Cheat" versions of the Homestar Runner characters. Their speaking voices are provided by Mike Chapman, but their singing voices are provided by Matt Chapman (or Missy Palmer in the case of Marzipan); in other words, the same as their normal versions.
Kim Possible: The Oh Boyz singing voices are not the same as their acting voices.
Liz Callaway is easily the queen of singing animated princesses. In addition to her Disney credits listed below, she provided the singing voice for the title character of Anastasia (voiced by Meg Ryan) and Odette in The Swan Princess (voiced by Michelle Nicastro).
Not only was the adult version of Anastasia given two voices, but so was the child version - for this one Lacey Chabert took over for Kirsten Dunst when it was time for the girl to sing.
The Disney Animated Canon is full of this trope nowadays (this isn't really the case though for older films in the series - i.e. pre 90's as they tended to virtually all be sung by their corresponding actors).
Pretty much everyone in Mulan. The heroine's VA was Ming-Na Wen, but her singing voice was provided by Lea Salonga. Shang's speaking voice was B.D. Wong, and his singing voice was Donny Osmond while in the Chinese version, his speaking and singing voice was (awesomely) Jackie Chan. Not even Grandmother Fa was safe from this. Her speaking voice was June Foray, and her singing voice (for her brief solo) was Marni Nixon (who was very famous for doing singing voices for Deborah Kerr, among others, in the 1950s).
Pretty much everybody in Aladdin had a different singing voice, save for Genie and Jafar (if you consider the sequels, Iago as well). Jasmine's singing was also performed by Lea Salonga.
Pocahontas' VA was Irene Bedard, and her singing voice is that of Judy Kuhn.
Neve Campbell (Kiara in The Lion King II: Simba's Pride). Oddly enough if one watches an episode of Party of Five, Neve Campbell's singing voice is actually quite decent.
Linda Larkin (Jasmine in both Aladdin sequels, replacing Lea Salonga from the first movie—which is perfect, seeing as it's ridiculously easy for someone to mistake Liz for Lea and vice versa).
Hercules had no fewer than three voices - Tate Donovan as adult Herc, Josh Keaton when he's younger, and Roger Bart when he's younger and singing.
Averted in the Mexican Spanish dub (see below).
Matthew Broderick can sing, but due to being more of a Lyric Baritone than a tenor, Joseph Williams replaces Simba for singing in The Lion King (and Cam Clarke afterwards). Young Simba is also replaced (Jason Weaver instead of Jonathan Taylor Thomas- and Evan Saucedo for the extra song in the 2003 DVD release), and Jeremy Irons sings some of Scar's lyrics, but partway through, the harsher lyrics were replaced by that of Jim Cummings.
In Who Framed Roger Rabbit, Kathleen Turner provided the speaking voice of Jessica Rabbit, while Amy Irving supplied her singing voice. In a rare reversal to most of the examples on this page, it's Amy Irving that gets credit while Kathleen Turner is omitted (amusingly, her performance model is credited).
The Nightmare Before Christmas has the main character, Jack, with a speaking voice provided by Chris Sarandon and singing voice provided by composer Danny Elfman. With no Burton/Elfman involvement in Oogie's Revenge, Chris Sarandon went on to sing all of Jack's songs in that game.
Inverted Trope - when casting, Elfman was chosen to provide Jack's singing parts, and then Sarandon was cast because his speaking voice sounded close enough to Elfman's.
In The Prince of Egypt, Val Kilmer's singing voice as Moses was provided by Amick Byram, Danny Glover (Jethro) was replaced by Broadway veteran Brian Stokes Mitchell, and Sally Dworsky dubbed the singing role for Miriam (Sandra Bullock). And proving that being a Dame is no barrier to such things, Helen Mirren has Linda Dee Shayne step in as the Queen's singing voice. (Averted, however, by Michelle Pfeiffer, Martin Short, Steve Martin and Ralph Fiennes.)
Other notable aversions in animated musical films:
Mel Gibson sings his part in Pocahontas - and would've sung a love duet, too, if they hadn't cut it for pacing reasons.
Kenneth Branagh and Kevin Kline (voice actors of Miguel and Tulio, respectively) both sing "It's Tough To Be A God" in The Road to El Dorado. Additionally, they recorded many of their lines together in the studio, which is sort of unusual.
Unusual, but it does happen. Animation voices are usually recorded separately because of scheduling issues, but sometimes actors are recorded together so they can bounce their performances off each other making the singing more Natural.
The Mexican dub of Hercules naturally averts this one, as Megara is voiced by the famous singer Tatiana, and Hercules is voiced by Ricky Martin. This also had the bizarre consequence of making Hercules speak like a reggaetonner.
Megara's English voice actress, Susan Egan, also did her own singing. She's an accomplished musical theatre actress, best known for originating the role of Belle in the stage adaptation of Beauty and the Beast.
All of the actors in Beauty and the Beast sing their own parts. In fact, Disney personnel went to New York to cast Broadway talent just to avert this trope.
A lot of Swedish dubs seems to do this too, usually hiring people from the musical scene to do the voice-acting. (The Swedish versions of Aladdin, Beauty and the Beast and The Lion King all feature the voice actors singing... or the singers voice-acting, whatever way you'd prefer to look at it.)
Iago doesn't sing in Aladdin, but he does in the sequels, and Gilbert Gottfried sings his part (but then, who could imitate Gilbert Gottfried's voice well enough to pass?). Broadway star Jerry Orbach also does his own singing as Saluk in the third movie.
Funnily, Gottfried's character of the Beetle in Thumbelina is sung by Randy Crenshaw.
Jodi Benson did her own singing as Ariel in The Little Mermaid. Granted, she was cast as her singing voice first...
Interestingly enough, Jodi Benson has voiced Ariel in EVERY incarnation of the character - the sequels, the TV series, and video games. She provides the voice of Ariel in any Disney created production - she even provided her voice for the Ariel's Undersea Adventure Dark Ride at Disney Parks.
In Frozen, everyone, with the exception of 5-year-old Anna (where Livvy Stubenrauch was dubbed by Katie Lopez) provide their own singing parts. And ALL members of the main cast get at least one song to themselves.
In Winnie the Pooh, all the singing is done by the main cast. Kanga is even voiced by one of the film's songwriters, Kristin Anderson-Lopez (who would go on to write for Frozen, with her husband Robert).
In Cats Don't Dance, Sawyer's singing voice was provided by Natalie Cole, and the speaking voice was Jasmine Guy. Likewise, Darla Dimple's singing voice is by Lindsay Ridgeway, and her speaking voice by Ashley Peldon. Averted with main character Danny, spoken and sung by actual musical theatre actor Scott Bakula.
Jem / Jerrica of Jem had a speaking voice provided by Samantha Newark, but a singing voice provided by Britta Philips.
Rival Pizzazz was voiced by Patricia Albrecht when speaking, and Ellen Bernfeld (aka disco singer Menage) when singing.
Ellen Bernfeld also did backing vocals for The Holograms and The Misfits, and was the singing voice of Roxy in her only solo song. Roxy's speaking voice actress was Bobbie Block.
Riot of The Stingers spoke with the voice of Townsend Coleman and sang with the voice of Gordon Grody (who went on to become Lady Gaga's voice coach).
The other two Stingers were also dubbed for singing. When speaking, Minx was Kath Soucie and Rapture was Ellen Gerstell. For singing, both of them were usually dubbed by Diva Grey, but for Rapture's two solo lines in the song "Destiny", she was dubbed by Vicki Sue Robinson, the disco singer of "Turn the Beat Around" fame!
When Kimber and Stormer sang a duet, they were dubbed over by Florence Warner and Lani Grover respectively, though Cathianne Blore and Susan Blu perform their speaking lines. Interestingly enough, their singing voices don't match their speaking voices at all.
All of this despite the fact that many of the speaking voice actors have done some singing, including JEM's speaking voice actress, Samantha Newmark, who is a professional singer.
The Family Guy episode "Don't Make Me Over" saw the Griffins forming a family band fronted by Meg. Trouble is, Meg's voice actress, Mila Kunis, can't sing (unlike Lacey Chabert, who originally voiced Meg - see Anastasia above), so they called in Tara Strong to perform Meg's song. In Stewie Griffin: The Untold Story, Ali Hills does Meg's singing voice.
Mila Kunis actually sang a line in a Sound of Music parody in the episode "Mr. Saturday Knight". On the DVD commentary, she claims she sounds "like shit".
It's not the first time Kevin Conroy has sung in the DCAU, either—in the Batman Beyond episode "Out of the Past", Bruce and Terry see a performance of "Batman—The Musical!". Kevin Conroy provides the singing voice for the onstage Batman (as does Adrienne Barbeau for the onstage Catwoman).
Mark Hamill and Paul Williams also sing for the stage Joker and Penguin but you can just barely make them out because they sing in unison.
In Lady and the Tramp II Scamp's Adventure there are three examples of this Buster's speaking voice is Chazz Palminteri while his singing voice is Jess Harnell, Scamp's speaking voice is Scott Wolf and his singing voice is Roger Bart, and Angel's speaking voice is Alyssa Milano and her singing voice is Susan Egan.
It's funny that the singing voice for Hercules and Scamp is Roger Bart, and Susan Egan the voice for Meg is the singing voice of Angel, Scamp's girlfriend.
In the Baby Blues episode "World's Greatest Dad" the scantily clad big busted Birthday Lady's speaking voice was Kath Soucie and her singing voice by Elizabeth Daily.
In the animated The King and I, as like its live-action counterpart, Anna had a separate voice actor as her singing voice.
In an episode of King of the Hill the singing voice of Boomhauer, whose regular speaking voice is by Mike Judge, was performed by country singer Vince Gill.
In Recess, Mikey's speaking voice is Jason Davis, but his singing voice is performed by Robert Goulet. A whole episode was dedicated to his newly discovered singing talent, and it's later revealed he can also speak in this voice when he uses it to spread a rumor.
This could be a parody or subversion, seeing as his singing voice obviously sounds absolutely nothing like his normal voice. To quote a kindergartner in Recess: School's Out, after he sings his farewell to TJ, "Big kid sing good."
When the main six perform "Green Tambourine" for the ending credits of the movie, the rest of the main six have different singing voices, with the sole exceptions of Vince (Ricky D`Shon Colins) and Spinelli (Pamela Segal). Interestingly enough, Gus (Courtland Mead) had his singing voice performed by Blake Ewing, the voice of Menlo, and Gretchen (Ashley Johnson) had hers by Anndi McAffee, the voice of Ashley A.
Any other time the characters sing (aside from Mikey), they keep their regular voices. On one occasion, Miss Grotke even gets her time to shine, and...it's...adorable.
Sonic Underground had the three hedgehog protagonists (yes, even the girl) voiced by the same voice actor, Jaleel White. However, when it came to the Once an Episode singing segment, they were voiced by three separate Voice Actors: Sam Vincent for Sonic, Tyley Ross for Manic and Louise Vallance for Sonia.
In the Danny Phantom episode "Fanning the Flames", the song sung by Ember was by a woman named Robin Kimissel while her main actress is Tara Strong. Strangely, this is the only incident of that happening. Ember sings another song in another episode which as far as anyone knows, Tara Strong does. Robin Kimiseel only does one episode and is never heard from again.
Kimissel was also the singing voice for Penny Sanchez. Rudy and Snap kept their regular voices.
In an episode of Rocko's Modern Life Filbert discovers he has a talent for lounge singing. His regular speaking voice was done by Doug Lawrence and his singing voice by Tom Kenny (Heffer), who in addition to voice acting is also a professional singer.
There are a couple of examples of this in the animated film Rock and Rule. Depending on which version you watch, Omar's speaking voice is either done by Paul Le Mat in the film, or Gregory Salata in the TV version; in both versions, his singing voice is done by Robin Zander. Angel's speaking voice is Susan Roman while her singing voice is Deborah Harry, and Mok's speaking voice is Don Francks while his singing voice is Lou Reed.
When Janet Waldo voiced Alice in Hanna-Barbera's TV adaptation of Alice in Wonderland, Doris Drew provided the singing voice. Waldo and Drew sound nothing alike. Waldo herself is actually a very good singer as evidenced in some early radio performances, so why they felt the need to replace her at all remains a mystery.
Taken to the point of parody on Phineas and Ferb, where (British) Ferb will sing with completely different accents for reggae or rap songs. Most of the other characters sing with the voice actors' voices, however.
And an in-universe example from the same, during the "Summer Belongs to You" special, Phineas hires Clay Aiken for his voice for one musical number, and Ferb gets Chaka Khan. It is obviously lampshaded.
Also lampshaded with Linda, who admits that her "Lindana" career was done by lip-syncing. In real life Linda is voiced by Caroline Rhea while "Lindana" is performed by Olivia Olson, who also voices (and sings for) Vanessa.
Stacy's voice is usually that of Kelly Hu, but here singing voice is that of Laura Dickinson. Strangely, Dickinson provided her speaking voice as well in "Phineas and Ferb Get Busted!"
In The Rescuers Down Under, the villain McLeach is voiced by George C. Scott, but during the part where he sings his twisted version of "Home on the Range" his singing is done by Frank Welker.
While SpongeBob SquarePants often sings in his normal voice, on special occasions he shows off a fantastic singing voice that sounds nothing like him, with him being voiced by a different guest singer every time.
In Toy Story 2, Jessie is voiced by Joan Cusack, but her yodeling was by the late Mary Kay Bergman. Wheezy (voiced by Pixar Regular Joe Ranft) sings a reprise of the original film's "You've Got a Friend in Me" at the end, sung by Robert Goulet. The series has many first-person songs such as "When She Loved Me", "You've Got a Friend in Me", "Strange Things" and "I Will Go Sailing No More", but it's more of "music to fit the situation" instead of "character singing."
Averted in Monsters, Inc., where Billy Crystal and John Goodman sing in character as Mike and Sulley over the end credits.
In The Flintstones, Wilma and Betty both had several different singing voices. None of them sounded anything like their speaking voices.
Notably averted throughout Total Drama World Tour. However, some autotuning was required to improve the quality of several characters, especially in "Come Fly With Us." The lack of this probably explains why Cody sings so little, despite lasting second-longest out of a team that was called to perform more than any other. Notably Ezekiel and Tyler, also voiced by Peter Oldring, don't sing much either. (Of course, you'll find plenty of fangirls who still like Cody's singing anyway...)
In My Little Pony: Friendship Is Magic a lot of the characters get singing doubles: Rebecca Shoichet for Twilight Sparkle, Shannon Chan-Kent for Pinkie Pie, Kazumi Evans for Rarity and Luna, Michelle Creber for Sweetie Belle. Amusingly, Michelle also provides the speaking and singing voices for Apple Bloom, which sometimes leads to Sweetie sounding inexplicably Southern when she sings.
Averted in the Season 3 episode "Sleepless in Ponyville". Claire Corlett, who only did Sweetie's speaking voice at the time, turns in a hilariously awful, pony-friendly rendition of "99 Bottles of Beer on the Wall". The aversion is completed in Season 4; as of "Flight to the Finish", Claire is singing Sweetie's part and doing an excellent job of it.
While Pinkie Pie's singing voice is normally provided by Shannon Chan-Kent, her speaking voice Andrea Libman still does her own singing as Fluttershy, and even Pinkie on occasion. According to Libman, this is because Pinkie's speaking voice can be very straining for her; one can only imagine doing the singing voice would be even harder on her vocal chords. Pinkie Pie's Smile Song notably has Andrea Libman providing backing vocals, making it a rare case where both singing and voice actors for Pinkie Pie are heard together.
This is averted with Rainbow Dash and Applejack (both voiced by Ashleigh Ball, a professional singer). Amusingly enough, this briefly causes Applejack's singing voice to sound much closer to the voice Ashleigh uses for Rainbow Dash in AJ's solo on "At the Gala". She even lacks her accent, present any other time Applejack sings.
In another odd case, Twilight Sparkle's speaking voice actress Tara Strong is more than capable of singing herself (heck, she's even been the singing double to other actresses before!), but her voice is recorded separately from other actors in the show; she's the only Hollywood-based actor while all the others record in Canada. One assumes that since all the songs are recorded as ensemble they prefer all the singers are there.
While afflicted with a deep male voice in "Filli Vanilli", Fluttershy has two different male actors for her speaking and singing parts. This is averted in "Bridle Gossip", where Fluttershy is voiced by a different male actor who handles both parts.
Ponytones member Torch Song's speaking voice is Cathy Weseluck, while her singing voice is Jerrica Santos, the singer of Equestria Girls' end credits song, "A Friend For Life".
In the Italian dub, Applejack, Rainbow Dash and Scootaloo have the same singing voice. Their rendition of "Winter Wrap Up" makes the former two really obvious.
In the Looney Tunes movie Daffy Duck's Quackbusters, Daffy's singing voice is provided by Mel Torme. Lampshaded though, in that Daffy swallows a bottle of mouthwash designed to give him Mel Torme's voice.
This may have been the inspiration for the Duck Dodgers episode "Talent Show A-Go-Go", in which Dodgers uses some Applied Phlebotinum to swap voices with Tom Jones. In addition to Jones voicing Dodgers, we also get Joe Alaskey voicing Tom Jones trying to sing while "sounding like Daffy Duck".
This was averted many times over the course of the series, notably in The 13 Ghosts of Scooby-Doo where Don Messick, Casey Kasem, and Susan Blu do their own singing in-character as Scooby, Scrappy, Shaggy, and Flim-Flam respectively. In addition, Scott Innes did his own singing for several Scooby-related songs in the early 2000s as Scooby and Shaggy. It helps that he's a professional singer (he even WROTE some official Scooby-Doo songs).
Averted again in the two Mystery Inc. episodes featuring the Hex Girls. Jennifer Hale (Thorn), Grey Delisle (Daphne), Jane Weidlin (Dusk), and Kimberly Brooks (Luna) all sing in the songs performed within the show. Especially Daphne, who gets a full songnote the other two songs were cut off for the villain to make his dramatic entrance. devoted to her shaky relationship with Fred.
In the tv special Easter Fever the villain Madame egg was voiced by Jeri Craden, however her singing voice was provided by a man singing in falsetto.
Zig-zagged all over the place in the Garfieldspecials. Lorenzo Music primarily voiced Garfield, and occasionally provided his singing voice as well (as he also was for Garfield and Friends). More often than not though, Lou Rawls, who also sang the opening numbers for each special, provided his singing voice instead. Sometimes both of them provided his singing voice for the same specials. For example, in "Garfield's Halloween Adventure, Music sings as Garfield for "What Should I Be," as well as a brief pirate song while later on Rawls sings as him for "I'm No Scaredy-Cat."
Parodied in South Park in "A Very Crappy Christmas" with the song "The Circle of Poo" (a parody of The Lion King), with Mr. Hankey's son Cornwallis talking in a young child's voice (Trey Parker) but singing with a deep man's voice (former Temptations member Louis Price).
Played straight in "Elementary School Musical" for some of the other students. A few of the girls, particularly Bebe, were voiced by Molly Pasuttinote a local LA singer and the wife of the show's composer Jamie Dunlap. She's also known for dubbing the opening theme of the anime "Moldiverfor their singing parts. Pasutti's two children, Alexis and Dylan Dunlap, filled in for providing the vocals for the other boys and girls.
An interesting variation occurs in the episode "Wing." Token sings "You'll Never Find Another Love Like Mine" by Lou Rawls, but since the actor couldn't sing they sped up the Lou Rawl's song instead. The sped up version sounds just like Token so it's pretty subtle.
Big Gay Al, while usually voiced by Matt Stone, has his singing voice provided by Trey Parker in the movie.
The Norwegian dub of Tiny Toon Adventures avoided this for the most part as almost all the characters has the same speaking/singing voices... except for Buster, whose voice actor apparently couldn't sing. As such, his singing voice was provided by the actor who voiced Gogo, Dizzy and Daffy, and sounded absolutely nothing like his speaking one.
On Littlest Pet Shop (2012), Penny Ling is voiced by Jocelyn Loewen, but her singing voice is Laura Hastings. Also, Zoe Trent is voiced by Nicole Oliver, with Kylee Epp as her singing voice. Oddly, the singing doubles have no other TV credits whatsoever.
In Rock and Rule, none of the characters who sing in the movie are done by their voice actors. Mok though, is a unique case because he has two, and they are done by none other than Lou Reed and Iggy Pop.
In the House of Mouse episode "The Three Caballeros" Panchito is voiced by Carlos Alazraqui his singing voice was done by Rob Paulsen.
In the feature film Hey There, It's Yogi Bear, Yogi's singing voice during the gondola scene is that of James Darren, which Boo-Boo lampshades during the song.
In Histeria! often times during the songs the kids singing voices were dubbed by adults like Loud Kiddington who's regular speaking voice was Cody Ruegger his singing voice was often done by Rob Paulsen when he wasn't singing in character, Charity Baazar who's regular speaking voice was Lorraine Newman (who was already an adult) her singing voice was provided by song writer Julie Bernstein.