If you recognise the actor in a bit part, it will probably turn out not to be such a small role after all; it will be The Big Bad, or the murderer, or someone else who is a key to whatever mystery the show revolves around. Usually, their true identity is not revealed until the final act. This is often referred to as the Law of Economy of Characters in film criticism. This is especially prevalent in dubbed anime series with Loads and Loads of Characters. Often when you have a Hey, It's That Guy! moment, a seemingly insignificant character will later end up having a large role. Even if Anyone Can Die, a character voiced by Steve Blum will rarely be Killed Off for Real (until the finale). The converse of this would be Small Role, Big Impact, where the part is small but juicy enough to justify casting a talented actor.
SubtropesContractual Immortality, Conspicuously Light Patch, Chekhov's Gun. May be a Final Girl.
- Tru Calling: Jack Harper (played by Jason Priestly) started off a paramedic who would come in, drop off a dead body, and provided the series with what seemed to be some minor flirtation. Then by the beginning of season 2, he's the anti-Tru villain who is the antagonist of nearly every episode.
- The Pretender: The two-parter "Bloodlines" stars Haley Joel Osment. Jarod must identify which one of three children is a genius. Since two of the children are unknown child actors and the last one was the lead in The Sixth Sense the year after appearing on this show, it's not hard for a post-1999 audience to guess which one it is.
- Baccano!: A seemingly ordinary guy who works on the train (played by Masakazu Morita) gets killed fairly early on in episode 2. Then came episode 9 and it was revealed that he is actually The Rail Tracer and he gets to play against the seiyuu's known roles.
- Tommy: In the film, Tommy is played by Roger Daltrey, a not-so-subtle clue that he might not be mute for the entire movie.
- Even before there was a voice actor to indicate it, Fairy Tail had one of these. Sure, Siegrain just acted like a background character who'd comment on the cast's adventures, but the first time he does this is the first page, before the cast even shows up, and even that isn't as telling as the fact that he's given the exact same character design as one of the more popular characters from Hiro Mashima's previous manga.
- Frequently subverted in South Park, who often have famous guest stars voice acting bit parts; in one case, a turkey. Which gets no lines except to make gobbling noises.
- Lost: For their first appearance, Mark Pellegrino and Titus Welliver were credited as playing "Man #1" and "Man #2". Turned out, they were in fact cast as Jacob and his nemesis, aka "The Smoke Monster" - two cornerstone mythology figures in the show.
- David Morse makes two fleeting appearances in some early scenes in Twelve Monkeys, where he plays a creepily cheery scientist who attends a book signing put on by one of the main characters. In the final scene he turns out to be the terrorist who was actually responsible for starting the plague that put the movie's time-travelling plot in motion.
- In the movie Equilibrium, William Fichtner's distinctive features are visible in a crowd shot. It's some time before he makes a speaking appearance.
- In The Hurt Locker, this is surprisingly subverted with major actors three times; Ralph Fiennes, David Morse and Guy Pearce all have less than 10 minutes screen time, and Fiennes' and Pearce's characters are so minor they both die mid-scene.
- In RED, Morgan Freeman gets one scene as an old friend of the protagonist's, before being "killed off" offscreen. Yeah, right.
- In the Doctor Who episode "Utopia", Sir Derek Jacobi appears in a one-off guest role as the kindly scientist Professor Yana...who's revealed to be the Doctor's nemesis the Master, one of the most iconic villains in the show's history.
- DJ Sagara in Kamen Rider Gaim.