->''"Don't I know you?"''
-->-- '''[[Creator/DavidWarner Lord Vultare to Baydool]]''', ''Film/QuestOfTheDeltaKnights''

A guest appearance by someone with a personal or prior professional relationship with one of the cast members of the show, such as Rhea Perlman appearing on ''Series/{{Becker}}'', Creator/ChristopherLloyd appearing on ''Series/SpinCity'', or Creator/HelenHunt appearing on ''WesternAnimation/TheSimpsons''. More often than not the guest actor will be playing an OldFriend of the relevant character, whom they haven't seen in years.

Subtrope of CastingGag. Liable to be a LargeHam. Expect numerous {{Actor Allusion}}s. Compare RealLifeRelative. Not to be confused with OldFriend, RememberTheNewGuy or BeleagueredChildhoodFriend, but can overlap with any of them. Compare RelationshipVoiceActor.

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!!Examples:

Live Action TV examples [[IWantYouToMeetAnOldFriendOfMine.LiveActionTV have their own page]].

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[[folder:Anime]]
* Episodes 42 and 43 of the ''Manga/AngelHeart'' anime series involves [[Manga/CityHunter Ryo Saeba]] (who is voiced by Creator/AkiraKamiya) dating a news reporter voiced by Creator/YurikoYamamoto. Kamiya and Yamamoto previously played [[StarCrossedLovers Kenshiro and Yuria]] in the original 80's version of ''[[Anime/FistOfTheNorthStar Hokuto no Ken]]''.
* ''LightNovel/SpiceAndWolf'' appears to do this in both Japanese and English. In the former, the two leads are played by Creator/JunFukuyama and Creator/AmiKoshimizu, who also played opposite each other as Lelouch and Kallen in ''Anime/CodeGeass''. In the latter, the leads are played by Creator/JMichaelTatum and Creator/BrinaPalencia, who also play the leads in ''Manga/BlackButler''.
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[[folder:Film]]
* All Creator/ChristopherGuest films feature members of his ProductionPosse in different combinations, but it is particularly noticeable in ''Film/AMightyWind''; the Folksmen are played by the three main members of [[Film/ThisIsSpinalTap Spinal Tap]]. The video for a song from their 60s folk rock phase is clearly a ShoutOut to "Listen To The Flower People".
* Extreme example: In the ''Series/MysteryScienceTheater3000''-featured film ''Film/QuestOfTheDeltaKnights'' all sorts of hilariously awkward dialogue of this sort occurs between the BigBad (Creator/DavidWarner) and TheMentor (Creator/DavidWarner).
-->'''Crow''': "Creator/DavidWarner, you're under arrest by the order of Creator/DavidWarner!"
* In ''Film/{{Maverick}}'' (directed by Creator/RichardDonner), Bret Maverick (played by Creator/MelGibson) is in a bank that is held up by a gang, one of whom is played by Danny Glover (Gibson's co-star from the ''Film/LethalWeapon'' movies, also directed by Donner); the two men almost appear to recognise each other, but then dismiss the notion. (Then, to cement the association, as Glover's character is mounting his horse for a getaway he is heard to say, "I'm gettin' too old for this shit!" - Roger Murtaugh's famous catchphrase from ''Film/LethalWeapon''.)
* In the epilogue of ''Film/HarryPotterAndTheDeathlyHallows, Part 2'', [[spoiler: Draco Malfoy's wife is played by Tom Felton's real-life girlfriend]].
* In ''The Senator Was Indiscreet'', a Creator/WilliamPowell vehicle, the final scene reveals that his wife, unseen till now, is Myrna Loy, who co-starred as his wife in numerous movies including ''Film/TheThinMan'' series.
* Seeing Creator/JamesSpader as the main villain opposing a group led by Creator/RobertDowneyJr in ''Film/AvengersAgeOfUltron'' is amusing, considering the two had previously worked together a few times in the 1980s. They actually played best friends in ''Tuff Turf'', as well as slightly antagonistic associates in ''Film/LessThanZero''.
* Creator/JohnCho and Creator/AntonYelchin, who played Sulu and Chekov in the ''Franchise/StarTrek'' "Kelvin Timeline" films that started with [[Film/StarTrek the 2009 reboot]], previously crossed paths before in the 2001 film ''Delivering Milo''.
* ''Disney/BeautyAndTheBeast'' featured Creator/JerryOrbach as Lumiere and Creator/AngelaLansbury as Mrs. Potts. They were very good friends, having worked together on Broadway and television. Notably, Orbach had a recurring role as hardboiled detective Harry [=McGraw=] in Landsbury's ''Series/MurderSheWrote''.
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[[folder:Professional Wrestling]]
* After being defeated by Son of Havok at Wrestling/LuchaUnderground, Sexy Star took him on with Wrestling/ChavoGuerreroJr. Havok, who some wrestling might have known better as Matt Cross, in turn teamed up with fellow Tough Enough contestant Wrestling/IvelisseVelez.[[/folder]]

[[folder:Theatre]]
* Creator/CatherineTate and Creator/DavidTennant of ''Series/DoctorWho'' fame were reunited for an onstage production of Creator/WilliamShakespeare's ''Theatre/MuchAdoAboutNothing''. They are both prominently featured in its advertising. (The two are also close friends in real life.)
* ''Theatre/{{Camelot}}'' was written and originally produced by much of the same team responsible for ''Theatre/MyFairLady'' (including director Moss Hart in the last Broadway show of his life). Not only did Creator/JulieAndrews have the starring role in both productions, but Robert Coote, who was Pickering in ''My Fair Lady'', returned as Sir Pellinore in ''Camelot''.
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[[folder:Video Games]]
* ''VideoGame/MetalGearSolid4GunsOfThePatriots'': In the Japanese dub, Snake is voiced by Creator/AkioOhtsuka. When [[spoiler: the older Big Boss, who Snake was cloned from, appears at the very end of the game]], he was voiced by Akio's real-life father Creator/ChikaoOhtsuka.
* In the ''Franchise/MassEffect'' series Female Shepard and Ashley Williams are voiced by Creator/JenniferHale and Creator/KimberlyBrooks. The two have worked together as partners before... specifically band-mates Thorn and Luna from the various ''Franchise/ScoobyDoo'' movies and shows. This makes it all the more funnier if you have a female Shepard and always include Ashley in your squad and then turn the Hex Girls song on while playing.
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[[folder:Web Comics]]
* ''Webcomic/{{Weregeek}}'' shows how not to let one's family and LARP spoil each other: [[http://www.weregeek.com/2012/10/01/ meet Alice and her kid]].
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[[folder:Western Animation]]
* One of the best moments of ''WesternAnimation/SharkTale'' was when Creator/RobertDeNiro said to Creator/MartinScorsese, "We've worked together for a real long time."
* In the ''WesternAnimation/BatmanTheAnimatedSeries'' episode, "Beware the Grey Ghost", the Gray Ghost (a thinly veiled black and white Batman TV show copy) is voiced by Adam West.
** The Grey Ghost is also inspired by Radio/TheShadow, who himself inspired Batman.
* In ''WesternAnimation/BatmanTheBraveAndTheBold'' Blue Beetle's best friend Paco is played by Creator/JasonMarsden, who previously played Eric Matthews' best friend, er, [[TheDanza Jason Marsden]] on ''Series/BoyMeetsWorld'', and is Will Freidle's best friend in RealLife.
** This sort of thing happens a lot with these two.
* Also from ''WesternAnimation/BatmanTheBraveAndTheBold'', [[Franchise/DCAnimatedUniverse Kevin Conroy]], the voice of Batman from the 90s animated series, played the Phantom Stranger in "Chill of the Night!" alongside Creator/MarkHamill, who famously played the Joker in that series, as the Spectre. The episode also featured Creator/AdamWest as Thomas Wayne and Julie Newmar as Martha Wayne.
* The episode of ''WesternAnimation/TheBatman'' that introduced Robin featured Kevin Conroy (Batman from B:TAS) as Dick Grayson's father and Mark Hamill (Joker from same) as Tony Zucco.
** Also from the episode that introduced Robin with Mark Hamill was Creator/GreyDeLisle, who voiced Dick Grayson's mother. Hamill and [=DeLisle=] voiced father and daughter Ozai and Azula on ''WesternAnimation/AvatarTheLastAirbender''.
* When Pleakley's family comes to visit on ''WesternAnimation/LiloAndStitchTheSeries'', they are voiced by many of Kevin [=MacDonald=]'s former castmates from ''Series/TheKidsInTheHall''. The only Kid in the Hall who didn't voice a family member voiced a preacher in that episode.
* In the sequels to Disney's ''Disney/{{Cinderella}}'', Prince Charming is voiced by [[WesternAnimation/SpiderManTheAnimatedSeries Christopher Barnes]] and Cinderella herself is now voiced by Jennifer Hale, AKA The Black Cat from the same series.
** Also, during the run of said series, Robert Hays reprised his role of WesternAnimation/IronMan for [[CrossOver some team-ups]] with Spider-Man. Hays and Barnes previously appeared together on the ''Series/{{Starman}}'' TV series and both were reportedly thrilled with working together again.
* Creator/TaraStrong and Creator/CreeSummer have been friends since childhood, even growing up together, and these days do a lot of voice-over work together. In other words, if you hear one of them in a given series, you're likely to hear at least one of the other two in the same series at some point.
** They've done enough shows together that their [[WesternAnimation/DrawnTogether respective characters]] eventually parodied the infamous SweepsWeekLesbianKiss.
** A lot of cartoon voice actors (see RelationshipVoiceActor) do this with people like Tara and Cree, as well as Creator/GreyDeLisle, Creator/TomKenny, Creator/KevinMichaelRichardson, Creator/RobPaulsen, Creator/CarlosAlazraqui, the list could go on.
* In ''WesternAnimation/TheSimpsons'', Sideshow Bob is played by Creator/KelseyGrammer. His brother and father are played by Creator/DavidHydePierce and John Mahoney respectively, who played Series/{{Frasier}}'s brother and father.
* Creator/BrendaSong played a rival to Music/AshleyTisdale's Candace on ''WesternAnimation/PhineasAndFerb''.
** Thomas Sangster played a young boy with a PrecociousCrush on Olivia Olsen's character in ''Film/LoveActually''--so when they were cast Ferb and Vanessa, Ferb's crush on Vanessa became a running gag.
* One episode of ''WesternAnimation/CliffordTheBigRedDog'' had T-Bone (voiced by Kel Mitchell) meeting an old friend, Hamburger (Played by Kenan Thompson). If you're old enough, you'd remember that both of them starred together in [[Series/KenanAndKel two]] [[Series/AllThat shows]] prior to breaking up due to creative differences.
* ''WesternAnimation/TheAvengersEarthsMightiestHeroes'': [[WesternAnimation/DannyPhantom David Kaufman]] showed up at the beginning of season 2 reprising his role of the [[Franchise/FantasticFour Human Torch]] from past Marvel video games. Regular series heroine the Wasp is voiced by Colleen O'Shaughnessey, who voiced Danny's sister Jazz Fenton. Reportedly the two were excited to be working together again.
* In ''WesternAnimation/AvatarTheLastAirbender'', Creator/GreyDeLisle voices Azula, and Creator/MarkHamill voices her father, Fire Lord Ozai. In a third-season episode of ''WesternAnimation/DannyPhantom'', the ghost of the week, Undergrowth, is voiced by Mark Hamill, and Sam Manson is voiced by Grey [=DeLisle=]. When Undergrowth takes control of Sam's mind, she even calls him "father".
* In ''WesternAnimation/TheMightyB'', Andy Richter voices Creator/AmyPoehler's little brother. On ''Series/LateNight with Creator/ConanOBrien'', Poehler played Richter's little sister in a few sketches in the late 90s.
* In the ''WesternAnimation/AdventureTime'' episode "Everything's Jake", the character Jake is trapped in his own body and meets a guy called Goose. Although Jake has never seen Goose before, Goose claims that Jake is an old friend. This is because Goose's voice actor, Creator/BillyWest, and Jake's voice actor, Creator/JohnDiMaggio, voiced the main characters Fry and Bender in ''WesternAnimation/{{Futurama}}''.
* In ''WesternAnimation/StevenUniverse'', Greg Universe and his former manager, Marty, are voiced by Tom Scharpling and Jon Wurster of radio show-turned-podcast ''Radio/TheBestShow''. Compounding the CastingGag is that despite the real-life duo being great friends and well-known comedy performers, Marty was such an utterly despicable black hole of a person (similar to awful characters Wurster used to play on WFMU, like the Gorch or Timmy von Trimble) and abused Greg so badly that Greg now considers him "dead to me", [[spoiler:even though he was indirectly responsible for Greg meeting Rose]].
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