Woody: You actually think you are the Buzz Lightyear? All this time I thought it was an act! Hey everyone, look! It's the real Buzz Lightyear!
A character performs an action that should be against their true nature/self-interest (such as getting angry at an ally, making a declaration of love, appearing to go crazy), until The Reveal that it's not an act: they really are that angry/in love/insane/etc. Sometimes the character is an impersonator, with their action being entirely in-character for both personas.
May cause My God, You Are Serious in onlookers.
Compare Not Brainwashed, If You're So Evil, Eat This Kitten. See also Enforced Method Acting, where actors produce the right reactions by being put in the same conditions as their characters, and Hidden Disdain Reveal, which may be a consequence of this.
As this is often The Reveal, beware spoilers.
Anime & Manga
- The Big Bad of EDENS ZERO turns out to be Ziggy, a friendly theme park Demon King robot and Shiki's adoptive grandpa, who Came Back Wrong after breaking down years ago. Since The Reveal happens right after Shiki finds out all his other robot friends were pretending to be evil to save him before they all died, Shiki holds out hope that Ziggy must also be acting. Ziggy's immediate response is to demolish the theme park—and soon the entire planet itself—with all the dead robots still there, establishing to readers that he's the villain whether they like it or not.
- Calvin and Hobbes: One arc begins with Calvin willingly leaving for school and acting disturbingly nice to his mother. She's left in complete confusion, while the reader learns that Calvin has used his cardboard box to make a pure good(y-two-shoes) clone of himself. Calvin being Calvin, the clone doesn't last long.
- A MOTHER FUCKING SURPRISE DON'T ASK QUESTIONS has the students of Hope's Peak Academy reveal they faked their deaths in the killing game, as part of a mystery game they put together for Makoto's birthday. Then Junko mentions that the scene where she killed Mukuro was real, to everyone's horror.
- The Mountain Andthe Wolf: From what we see of the Wolf's personality when he's around his Westerosi "allies" (where he appears as an Obviously Evil Boisterous Bruiser who openly supports Daenerys going on a rampage across the Seven Kingdoms to establish her authority) and when around his own men where there's no need to hide his true intentions, there's... very little difference between the two, even regretting her wasted potential when the transfer of power happens with little protest.
- Toy Story: When Buzz chews out Woody for opening his helmet, Woody realizes Buzz really thinks he's the one and only Buzz Lightyear and mocks him for it. It takes seeing an entire shelf of Buzz Lightyear toys to finally make Buzz find out the truth. In the sequel Buzz gets captured and replaced by a newer model under the same delusion, causing Andy's Buzz to groan in recognition.
- Harry Potter:
- Harry Potter and the Goblet of Fire: Mad-Eye Moody is famously averse to Death Eaters who avoided prison, as his job is to arrest them and his face is covered in scars from those who resisted. The Moody Harry meets during his fourth year was impersonated by a Death Eater who did go to prison (and is trying to revive Voldemort), and understandably hates those who claimed they'd been mind-controlled to avoid punishment, hence his punishing Malfoy by turning him into a ferret and passive-aggressive attitude towards Karkaroff (the son of a "reformed" Death Eater and one who sold out the others to save his skin, respectively).
- Harry Potter and the Half-Blood Prince: When suspected of being a Double Agent by Bellatrix, Snape has a long speech where he patiently takes apart her arguments, including one where he belittles Harry as a mediocre wizard who needs his friends' help to get anywhere. As we see in the last book, most of what he told Bellatrix was a lie and he was always against Voldemort, but his contempt for Harry was genuine, using very similar terms when speaking to Dumbledore about him.
- The Judge Dee Fan Sequel "Chinese Medicine For Murderers" has the judge look for a way to catch an incompetent doctor in the act. He sends his wife to complain of a headache, oblivious to her grouchy attitude, sour expression and the fact that she keeps massaging her temples. When she returns (having narrowly avoided being killed by the doctor's brilliant idea to treat a dozen people by burning huge amounts of rat poison in a stuffy room), the judge congratulates her on her idea of faking a headache. She returns to her room before the temptation to murder him becomes too strong.
- Lord Edgware Dies: Hastings sees Jane Wilkinson trying out widow's clothes with an air of great concentration, and clearly uninterested in such trivial matters as the murder of her husband. At the end of the story he confirms his impression that she really did only care about the clothes at the time even though she'd murdered said husband.
But when I think of her, I always see her the same way standing in her room at the Savoy trying on expensive black clothes with a serious absorbed face. I am convinced that that was no pose. She was being completely natural. Her plan had succeeded and therefore she had no further qualms and doubts. Neither do I think that she ever suffered one pang of remorse for the three crimes she had committed.
- For most of the first volume of The Hunger Games, Katniss believes Peeta is pretending to be in love with her as part of a plan to manipulate the sympathies of the audience to help them earn sponsors that might let them survive the game. It's only near the end of the book that it finally sinks in that every single thing Peeta ever said about loving her ever since the first day they met was entirely true.
- Later in the series, Finick Odair tells Katniss that he sympathises with her need to maintain the facade of being in love with Peeta since all his so-called "lovers" are actually patrons he's being prostituted to by President Snow. But after he saw how Katniss nearly lost her mind with panic when Peeta walked into an electrical hazard and his heart briefly stopped, he realised that Katniss really did love Peeta too, possibly even before she did herself.
- Wulfrik Wulfrik's stated reason for needing a lot of gold from Viglundr is to assemble an army to get his revenge on the sorcerer who backstabbed him by besieging the city he's hiding in. Not only is it entirely genuine, any Norscan would act the same. Viglundr gives him the ships and men he needs in exchange for most of the plunder from the city but wasn't counting on Wulfrik figuring out his and Sveinbjorn's plan, turning it against him, and then willingly sending their entire tribe to destruction.
- Blackadder: In the second season, Blackadder has had a man executed prematurely without anyone knowing, but the man's wife begs the queen for one last meeting. Blackadder is forced to impersonate him lest he get the chop, and does so with a bag over his head, insisting on Baldrick only allowing them two minutes. Blackadder manages to impersonate the husband to the point where she starts to go down on him, which of course is the moment an unusually-competent Baldrick comes in to declare that their time's up. Blackadder's "No it isn't" is entirely heartfelt.
- Constantly brought up in Canada's Worst Driver by the fact that these are real drivers.
- In Homestuck, Mom Lalonde is so ridiculously over-the-top in the way that she expresses her love for her daughter Rose that Rose assumes that she's just pretending to care as a means of Passive-Aggressive Kombat. It takes some Character Development for Rose to realize that her mother is being completely sincere and is just a naturally excessive person.
- The Legend of Korra: Mako and Bolin are held captive by Bolin's sort-of fiancee Eska and her brother Desna as Unalaq fuses with the evil spirit Vaatu. Bolin starts blubbering that he and Eska will never be together if the world is destroyed, prompting Eska to kiss and release him (as Mako and Desna share an "are you seeing this too?" look). As Mako and Bolin escape, Mako congratulates Bolin on his acting skills. Bolin mumbles something like "yeah... acting..." and sheds a Single Tear.