A con job or other circumstance requires a character to pose as another, usually powerful or important, person. However, it is eventually revealed that the character really IS that person. Frequently, this is a reveal to the would-be impostor as well as the other characters and the audience, while at other times, the "impostor" is aware of his or her true identity, but keeps it hidden for various reasons.
For this trope to apply, the real identity doesn't have to be the exact same person that is being impersonated, but rather has to be a person that fills the same role as the false identity. A long-lost relative, a member of the same group, or holder of the same position may work just as well.
Often overlaps with I Am Who? and Really Royalty Reveal. May well lead to a Your Costume Needs Work reaction from other characters, since Reality Is Unrealistic. Related to You Will Be Beethoven (where the character becomes the crucial person they're impersonating as part of a Stable Time Loop). Compare and contrast Mistaken for an Imposter where the character was never attempting to impersonate anyone.
Recursive Crossdressing is a Sub-Trope. For Halloween, I Am Going as Myself is another Sub-Trope that applies to (usually paranormal or costumed characters) who know their identity, but dress up as themselves for Halloween or a similar festive occasion. Accidental Truth is the Super-Trope. Compare Actually, I Am Him.
As this is frequently a plot twist, beware of spoilers in the examples below.
- The premise of Barrage involves Barrage, Prince of Industria, foisting his position and responsibility upon an Identical Stranger named Astro. Barrage then gets shot and killed, while Astro reluctantly takes his place in the royal palace. Many chapters later, Astro discovers that he was the real Prince all along, and the Barrage who died was really his clone.
- Fairy Tail:
- Carla claimed to be the Exceed's princess to prevent Edolas Erza from arresting her and Happy. Unbeknownst to her, it's revealed by the end of the arc that she really is Queen Chagot's daughter.
- A Fairy Tail member named Mest is introduced as an S-Class candidate in a Remember the New Guy? fashion, until the guild begins noticing they hardly know anything about "Mest" despite knowing him for years, prompting The Reveal that he's a Backstory Invader from the Magic Council named Doranbalt. Years after he returns to the Council, Makarov drops the bombshell that he really is a Fairy Tail member named Mest who infiltrated the Council to get information on The Empire, wiping his own memory and everyone else's memory of his existence (except for Makarov) in a hair-brained effort to reduce his chances of being discovered.
- In Diamond and Silver's Excellent Adventure, Silver Spoon gets paranoid about her allies possibly being someone else in disguise, and she checks them all for Latex Perfection masks. Princess Luna's face pops right off, revealing that she's actually... Princess Luna. When asked why she was disguised as herself, Luna answers that she can't remember why anymore, "But it sure seemed important at the time."
- Inverted in With This Ring when Arnold Munro visits an Amazonian tribe. Everyone mistakes him for his father Hugo Danner, who visited them decades ago and introduced them to his Super Serum, until he explains the mixup. Then Squire reveals that Arnold Munro passed away quietly years ago; the man standing among them really is Hugo, impersonating his son Arnold.
- In The Addams Family a conman pretends to be long-lost Uncle Fester. It turns out he really is Uncle Fester, but he has amnesia.
- Murder by Death: During the finale, each detective is claiming the killer to be a different person and each time he "confesses" and goes along with the story until the next detective enters and gives another identity. When Sam Diamond gives his he explains that the killer is the real Sam Diamond and he is an actor hired to play him. However the killer then denies this tale and later as everyone is leaving Sam admits that he actually is the real Sam Diamond. Why he made up the imposter story is left unexplained.
- The German film Phoenix features its protagonist, Nelly, being mistaken by her husband for a different woman. The husband thinks Nelly died in a concentration camp. He wishes to take her inheritance for himself, so he schemes to have this apparent lookalike pass for her. Nelly goes along with this because she's still in love with him. But she realizes what a treacherous scumbag he is at the end and walks away after revealing the truth to him.
- In The Tourist, Johnny Depp's character Frank is mistaken by the authorities to be a thief named Alexander Pearce. Near the end, Frank walks up to the bad guys and claims to be the real Alexander, putting on a fake British accent and explaining that he got plastic surgery. Then, after the cops arrest the bad guys, he reveals that he really is Alexander and has been playing the role of the hapless Frank the whole movie.
- Jennifer Nielson's Ascendance Trilogy: The False Prince has four orphan boys competing for the role of Prince Jaron, who disappeared at sea years ago. The protagonist, Sage, turns out to actually be Jaron, hiding his identity for reasons of his own.
- In the novel Brat Farrar by Josephine Tey, the title character is an impoverished jack-of-all-trades who is persuaded by a friend to take part in a scheme where he pretends to be Patrick Ashby, the heir to a wealthy aristocratic family, who went missing years before and was presumed to have committed suicide. Along the way, Brat comes to understand that Patrick was murdered and whoever knows he's not the real Patrick was likely the killer. It is eventually revealed that while Brat is (obviously) not really Patrick, his similarity in appearance is not a coincidence, as he's the illegitimate son of a n'er-do-well Ashby cousin, and he ends up being "adopted" into the family.
- In one of the Captain Future books by Edmond Hamilton, Planets in Peril, the title character goes into an alternate universe to impersonate an ancient hero who promised to return when needed. The ending reveals the alternate universe to actually be Earth All Along, with which information it becomes apparent that the ancient hero's name, Khaffr, is a half-recalled distortion of "Captain Future".
- The Chronicles of Narnia: The Horse and His Boy: Orphan Shasta gets mixed up with Archenlander Prince Corin in a non-voluntary Prince and Pauper plot, and goes along with it after he accidentally hears their secret plans and fears He Knows Too Much to be allowed to leave. By the end of the book, it turns out that he is Corin's long-lost twin brother, and so really was a Prince of Archenland all along.
- Codex Alera has Tavi defuse a tense situation involving a Canim ambassador by pretending to be an important figure. It's later revealed that Tavi is the prince and heir to the throne, though he didn't know it at the time. Moreover, as Canim can discern a person's relatives through their keen sense of smell, the ambassador knows the truth even before Tavi does.
- Terry Pratchett's Discworld
- Approached from the other end in Moving Pictures: the wizards decide to go to the movies, but as wizards can't be seen enjoying such base entertainments. So they go for disguises, and one of them comes up with the idea of twisting wire in their beards, so now they all look like regular people badly disguised as wizards. Which of course backfires when they need to identify themselves as wizards, but left the wires in.
- The same device is used again in Monstrous Regiment, wherein an entire troop of soldiers, excepting only its commanding officer, is composed of young women who have disguised themselves as men in order to join the army. When they decide to re-disguise themselves as washerwomen to infiltrate the enemy-occupied palace, they've been pretending to be men for so long that the enemy guards notice all kinds of "giveaways" like one of the "men" still having a spot of shaving cream under one ear. They end up having to flash the guards to prove their womanliness. The actually-male officer walks right in unchallenged.
- In The Dragons of Babel by Michael Swanwick, the king of Babel has been missing for a few decades. Will, the protagonist, falls in with a con man named Nat, who comes up with a plan to pass off Will as the king's bastard son and therefore the sole heir to the throne. In the end, it turns out that Nat is both the long-lost king and Will's biological father, meaning that Will really is the heir to the throne.
- The epilogue finds an older Will tracking down his teenaged daughter, who had been given up by her mother and doesn't know who her father is or of her own claim to the throne. It seems that Will is about to start running the same sort of scheme his own father did and for pretty much the same reason.
- In The Ivy Tree, by Mary Stewart, tourist Mary Grey is approached by Con Winslow and eventually agrees to impersonate his cousin Annabel, who as a teenager ran away from the family farm. Con's aim is to secure the inheritance of the farm for himself, since Annabel's grandfather is elderly. Mary's aim is to see her home and family again , because she really is Annabel.
- In the Polish book Pięć przygód detektywa Konopki, one of the stories involves criminals hijacking a passenger plane, and meeting on board a man who they believe to be the meek Detective Konopka disguised as a heavyweight boxer. They lower their guard around him, until suddenly he effortlessly punches them out. It turns out that he is, actually, a heavyweight boxer disguised as a detective disguised as a heavyweight boxer, who co-operated with the real detective to trap the criminals.
- Lloyd Alexander's Westmark has a similar situation to Anastasia in which a pair of con men must pass off an orphan girl as a lost princess. However, Mickle is aware of her identity the entire time and goes along with the deception in order to out the Evil Chancellor as a traitor.
- In Thrawn: Treason, when caught by a group of pirates on Tiquwe, Eli pretends that Assistant Director Ronan is merely a look-alike, whom they are using to infiltrate the local Imperial base, which would also explain their perfectly genuine passes (Eli claims they're very good fakes) and Ronan's uniform. To his credit, Ronan plays along, hamming up the stereotypical snobbishness of Imperial bureaucrats and making it look like an act.
- Donald A Wollheim's "The Man From The Future": The two protagonists convince a dwarf that they met on the subway to go to a Science Fiction Fan Convention where they will pretend to be a human from the far future. The punchline of this story is that they identified a real Time Traveller who happily played along (only revealing himself by shooting a heckler with a futuristic weapon).
- Star Wars Legends
- Early in the Legacy of the Force series, Luke and Mara Jade Skywalker need to sneak onto the planet Corellia, currently on the verge of war with the Galactic Alliance. They get past the heightened security by claiming to be actors playing the Skywalkers, here to shoot scenes for an upcoming movie. For added effect, they also hired several genuine actors to accompany them, supposedly playing the roles of their friends and family. One security guard thinks Luke looks nothing like the real deal, ignoring his protests that he can totally do backflips just like the legendary Jedi.
- In The Stormlight Archive, Lady Shallan Davar is engaged to Prince Adolin Kholin. On her way to meeting him, her ship is attacked by assassins targeting her mentor, and the boat is shipwrecked. She runs into a caravan going in the same direction, where she meets a con woman named Tyn. Tyn sees her as a fellow con artist, and Shallan goes along with it. Shallan passes herself off as a con woman who learned that the prince's fiancé died in a shipwreck; since Shallan is a minor, foreign noblewoman, the Alethi court hasn't met her, making her an easy target for a replacement. Her cover is blown when Tyn turns out to be a member of the group that tried to assassinate her mentor, and receives a detailed description of what the ward looks like.
- On How I Met Your Mother, one of Barney's plans for seducing women was called "Weekend at Barney's", a riff on the movie Weekend at Bernie's, where Barney pretends to be dead, but Ted and Marshall put sunglasses on him and move his limbs around with strings so that women will think he's alive and have sex with him. Robin points out that, if the woman is "tricked" into thinking Barney's alive, and Barney actually is alive, then the whole "pretending to be dead" step is completely pointless. Barney can't seem to comprehend this argument.
- In a Saturday Night Live Cold Open from 2007 Bill and Hillary Clinton have a Halloween masked ball. And who is that in the Barack Obama mask? Why it's none other than Barack Obama (As Himself).
Barack Obama: Well, you know, Hillary, I have nothing to hide. I enjoy being myself. I'm not going to change just because it's Halloween.
- The Importance of Being Earnest has Jack Worthing posing as "Ernest" in London to his friend Algernon and Love Interest Gwendolyn, while pretending in the countryside that "Ernest" is his wastrel younger brother. Algernon then goes to the countryside and assumes the "Ernest" identity in order to romance Jack's ward Cecily. Eventually, it is revealed that Jack is actually named Ernest and that Algernon really is his younger brother.
- Pokémon Sun and Moon introduces Fomantis and Lurantis, Grass Pokémon that resemble orchid mantises, insects that camouflage themselves as orchids to catch pollinating insects. Fans sometimes question why they aren't Bug types or part Bug but in truth, they are flowers that resemble bugs. So in the end, they are plants that resemble bugs that resemble plants.
- In Team Fortress 2, if a Spy disguises himself as an enemy Spy, his disguise will have a fake disguise to make it more convincing to the enemy. As this fake disguise is randomly chosen, it's possible for the Spy to be disguised as an enemy Spy, disguised as a Spy, meaning the Spy is wearing a disguise of himself to fool the enemy.
- In Wolfenstein II: The New Colossus, wanted terrorist and serial killer William J. "Terror Billy" Blazkowicz goes undercover as an actor playing himself in a propaganda movie for the Third Reich. Notable in that it only works because pretty much everyone under the Reich's jackboots (in other words, literally everyone) saw him get decapitated on live television, and No One Could Survive That!
- In El Goonish Shive, Grace and Ellen play a game of Spot the Imposter with Tedd with Grace pretending to be Ellen pretending to be Grace and Ellen pretending to be Grace in her "Claire" form.
- Girl Genius: Higgs, who by that point of the story has turned out to be a Jäger with an appearance unusually close to that of an ordinary human being, gets forced into a Jäger costume.
- One episode of Dude, That's My Ghost! has the rock star Billy Joe Cobra perform in a concert as a Billy Joe Cobra impersonator... because he's a ghost, and pretending to be himself after his most likely well-publicized death would raise a lot of awkward questions.