You know that feeling when you’re watching a TV show and you spot an actor you recognize, but can’t quite place them? Well, sometimes that might be because - continuity be damned - you previously saw them on that same show, just in a different role.

This happens a lot more than you may realize. Most of the time it’s a result of a series running for so long that bringing back a previous guest star in a different role isn’t going to ruin the audience’s suspension of disbelief, although in more recent years it’s become a more purposeful occurrence, worked into the fabric of a show’s narrative to provide a shocking rug-pull. Today we’re going to run down some of the most intriguing.

To stop things from getting silly, however, we’re not going to include cases where an actor was playing a straight-up clone, an alternative timeline version, or someone temporarily disguised as their regular character - otherwise it’d just be a list of every genre show ever. There’ll be no animation voices either - that’s just too common (sorry Simpsons fans). Here are 15 Actors Who Played Multiple Roles In The Same TV Show!

15. Terry O’Quinn as John Locke and The Man in Black - Lost

Lost was the last great show to come from the 22-odd-episode season structure (24 lasted a whole day longer, but it started earlier), and one of the ways it really secured that title is by using a trope that’s become incredibly common in the new golden age: ruthlessly offing main characters.

Boone, Shannon, Libby, Ana Lucia, Mr. Eko (most of the tail section survivors actually), Charlie, and Michael all bit the dust in the early years. However, by the fifth season the core cast was so embedded that maintaining the deadliness was tricky. So it was that when former paraplegic and all-round Man of Faith John Locke was killed, Damon Lindelof and Carlton Cuse made sure Terry O’Quinn still had work by bringing the character back to life when his corpse was returned to the island (it’s complicated, just go with it).

At first this was presumed to be Locke resurrected, but the season finale revealed that O’Quinn was actually playing the Man in Black (not that one), the human form of the island’s shapeshifting smoke monster. At first an impersonation, the MiB later found himself stuck into the John form, meaning O’Quinn played the part throughout the final season, while still returning to Locke in the flash-sideways timeline.

14. The Main Cast as The Main Characters and Doppelgangers - How I Met My Mother

While the show was ostensibly about how Josh Radnor became Bob Saget and met the mother, across its nine seasons How I Met Your Mother was more defined by its core group dynamic and a plethora of running gags – the Slap Bet, the Playbook, interventions, Barney’s blog, red cowboy boots and more.

One of the jokes actually relevant to the overarching plot was the doppelgangers: around Season 5 the gang started seeing doubles of each other around New York City, leading to Marshall and Lily making a pact to only try for a child when they’d found all five (the show was oddly obsessed with destiny). This meant that over the period of about a year each of the central quintet wound up playing another New York denizen – Josh Radnor was Mexican Wrestler Ted, Jason Segel Moustache Marshall, Cobie Smulders Lesbian Robin, Alyson Hannigan Stripper Lily and Neil Patrick Harris fertility doctor, Dr. John Stangel. It was legen… wait for it…

13. Anne Baxter as Zelda the Great and Olga, Queen of Cossacks - Batman

It’s best remembered for the elements in the movie – the bomb, the shark spray, the garish takes on iconic villains – but Adam West’s Batman TV series was far more prolific than just that, running for an eye-watering 120 episodes (over just three seasons, no less - the ’60s was a different time). What’s even more amazing is the calibre of actors it got: Caesar Romero was the freaking Joker, case closed.

It was so good at getting big name actors, it managed to have an Oscar-winner appear not once, but twice. Anne Baxter, who won Best Supporting Actress for The Razor’s Edge and was further nominated for TheEve it was All About, first appeared in Season 1 for a single two-parter as Zelda the Great, a magician who robbed a bank every April Fool’s Day. Then, a year later she returned for Season 3 as Olga, Queen of Cossacks, an accomplice and love interest for Egghead (played by Vincent Price, no less). This was actually just one part of a shift in Baxter’s career, who by the late-sixties had transitioned from the big screen to television, taking guest spots in a wide range of series.

12. Ali Larter as Niki and Jessica Sanders and Tracy Strauss - Heroes

Heroes never quite knew what to do with Nikki. While everyone else’s power set fulfilled some basic superhero desire – flying, time travel, precognition, healing – her Jekyll and Hyde relationship with the spectre of dead twin Jessica was pretty out there. Things were eventually consolidated by the single mother beating her demon and gaining super strength, but even then the writers struggled to make her interesting, bringing in another dark side, this time a short-lived imaginary friend, before giving up the ghost and just blowing up Ali Larter in the Season 2 finale.

In a move similar to what happened with Locke on Lost, the show didn’t want to ditch the actress despite ending the character, so the writers brought her back in Season 3 as ice-powered political advisor Tracy Strauss. It was eventually revealed Tracy was actually a third estranged sibling of Nikki and Jessica’s, although she was much more interesting than that connection suggested, with Larter finally getting some interesting story to play with (even if it was in late-season Heroes).

11. John Leguizamo as Orlando Calderone and Angelo Alvarez - Miami Vice

It may not hold up by modern TV standards, but Miami Vice was a pretty major show in the eighties, and its impact can still be felt today, not least in the stars it gave a career boost to: Liam Neeson, Bruce Willis, Steve Buscemi, Benicio del Toro, Jimmy Smitts Chris Rock, and a host of others that to list would take us way off track. In amongst them was John Leguizamo, who is notable not for what came after (although that’s certainly eclectic, with roles ranging from Ice Age to The Infiltator), but that he did the show twice.

His first appearance was as Orlando Calderone, the son of a gangster who had a particular vengeance with Tubbs. That role spanned two seasons, but wasn’t enough to write him off from appearing a few years later in Season 5, a drug dealer who found himself wrapped up in a neo-Nazi scheme.

10. Patton Oswalt as Eric, Billy and Sam Koenig - Agents of SHIELD

Although it took place in the Marvel Cinematic Universe and was in small ways influenced by the events of the movies, in its first season Agents of SHIELD had much more in common with standard network television procedurals than the blockbusting movies it shared a world with; the cast was a banterous ensemble embarking on often random monster-of-the-week style adventures.

As a result, aside from Samuel L. Jackson and Cobie Smulders, most of the show’s guest stars were more random than expected. One of the standouts was Patton Oswalt as the fastidious Eric Koenig, an aggressively by-the-book SHIELD agent who appeared late in the season for some comic relief as things got increasingly dark. He was swiftly killed, yet Oswalt wasn’t done with the show just yet; he re-emerged in the finale as Billy Koenig, a similarly personified, identical agent. It didn’t end there either, with the joke continuing and introducing him as another Koenig, Sam.

It’s widely accepted in the show this is a set of triplets with very similar career aspirations, although there’s enough suspicion to suggest they could be Life Model Decoys, robots that ran rampant in the Silver Age of Marvel comics.

9. Sheryl Lee as Laura Palmer and Maddy Ferguson - Twin Peaks

As Laura Palmer, the girl whose death motivates the uncovering of darkness beneath the eponymous Washington town, Sheryl Lee was almost barely in Twin Peaks at all – in theory she was only needed to play the body, then appear in a few pre-death video tapes and some typically Lynchian dream sequences before cashing her cheque. However, David Lynch was so impressed that he chose to introduce a new character for her to play; Laura’s cousin, Maddy, who over the course of the series develops from mousey bookworm into a Laura parallel, even eventually dying at the same killer’s hands.

The whole thing appears to be Lynch’s take on Vertigo, with similar themes of identity and replication, and, more pointedly, Maddy Ferguson taking her name from Kim Novak and James Stewart’s characters in the film.

Lee’s relationship with Twin Peaks continued to the movie, Fire Walk With Me, with her playing Laura in her final days, and she’s set to return in the long-anticipated Season 3 in 2017 (although how exactly is anyone’s guess)

8. Jerry Orbach as Frank Lehrmann and Lennie Brisco - Law and Order

Jerry Orbach was a lauded musical actor, appearing in broadway productions of Chicago, 42nd Street, The Fantasticks and Promises, Promises, but he’s likely best known to modern audiences for his vocal turn as Lumiere in Beauty and the Beast and Detective Lennie Brisco in Law & Order.

The latter was a particularly impressive run. He starred in 273 episodes of the show’s original series, bagging himself several prestigious award nominations, then reprised the role in Special Victims Unit, Criminal Intent and Trial By Jury (as well as a few video games).

Like with other long-running shows we’ve seen on this list, sometimes the sheer number of episodes meant that future stars had previous guest starred, and so it was with Orbach – a year before making detective, he’d been an attorney, defending a woman for her ex-husband’s murder.

7. The Core Cast as Various - American Horror Story

In the modern golden age of television, the biggest fear is overstaying your welcome and a story falling flat, going too far or becoming repetitive (hello to The Walking Dead). This is where anthology series premise became so attractive; you can have an overarching brand with a shared world or similar theme, but each season deals with different stories and thus avoids repetition. Some have flourished in this regard – Fargo – some floundered – True Detective and its dour Season 2 – but the most prolific by far is American Horror Story.

For this show, FX had each season take on a different chilling sub-genre, but the core cast remained, giving audiences an extra reason to come back each year; Evan Peters, Sarah Paulson and Lily Rabe have all appeared in all six stories, while plenty of the other regulars have come back multiple times.

Of course, this consistency has got fans theorising there’s a bigger link between seasons than this being a simple anthology – we’ve seen characters crossover seasons and creator Ryan Murphy has even hinted at it - but the true nature of it all - reincarnation, connected souls or other - is, as of writing, yet to be revealed.

6. Terry O’Quinn as Brian Tillman, Darius Michaud and Shadow Man - The X-Files

Although Lost is the most well-known case of Terry O’Quinn playing two characters on the same show, fitting for an actor who’s been working solidly since the mid-eighties, it wasn’t the first. Even more fittingly, that first time was on America’s previous great sci-fi obsession, The X-Files.

He first appeared as an army Lieutenant involved in genetic-memory-based murder story “Aubrey” from Season 2, then in the first movie, this time as an agent who enabled a mysterious cover-up (killing himself in the process), and finally in Season 9’s “Trust No 1” as full-on villain Shadow Man. Of course, being nineties television, these sort of recurring roles were to be expected and rarely picked up on.

Chris Carter must have had a soft spot for O’Quinn, though, because he also put him in Millennium (a show that crossed over with The X-Files after cancellation) and the short-lived Harsh Realm. All good training for Locke.

5. Summer Glau as Cameron and Allison Young - Terminator: The Sarah Conner Chronicles

Terminator may not have a had a good movie in twenty-five years, but the franchise’s output following Terminator 2: Judgement Day isn’t totally a barren nuclear apocalypse. The shining diamond in the rough is The Sarah Connor Chronicles, a continuation of the original timeline that returned the series to its roots, mashing up future resistance and time travel mechanics.

At the centre of this was geek-icon Summer Glau as turned Terminator Cameron. Through Glau, TSCC explored the robot psychology in a way that the main series had never even flirted with, and in doing so explored her model’s origins; it was revealed in Season 2 that Cameron was based on Allison Young, one of future resistance leader John Connor’s closest allies and thus the perfect target for a replacement infiltration unit.

This may technically breach the “no clones” stipulation from the start of the article, but it’s such a fascinating case, one that allowed the show to do more than the usual “which one is the real one?” conundrum that it deserves a mention.

4. Mark Lenard as Romulan Commander, Sarek and Klingon Captain - Star Trek

Mark Lenard is best remembered for his long-running tenure as Sarek, Spock’s Vulcan father in Star Trek. First appearing in the role in the show’s second season, then reprising it in the short-lived animated series, he eventually became a mainstay, appearing in four movies - The Search for Spock, The Voyage Home, The Final Frontier and The Undiscovered Country - and even a couple of episodes of The Next Generation. That’s quite a legacy.

But that’s not the whole of Lenard’s commitments to Trek. Before becoming a Vulcan, he played a Romulan Commander in Season 1. That’s fair enough – we’ll see in a little moment that it’s quite common for people to get promoted to bigger parts in sci-fi shows. The weird case is that, in The Motion Picture, which came after his early appearances as Sarek, he was popped up as a Klingon; it may be a movie, but that’s some strange continuity choices. Clearly the part of Spock’s father wasn’t deemed important enough to have consistency until the later films.

3. Rose Abdoo as Gypsy and Berta - Gilmore Girls: A Year in the Life

Fitting of a show built on sly, wink-wink humour, the long-anticipated Gilmore Girls reboot, A Year in the Life was full of jokes for long-term fans to cheer along with (and tear-up to). One of its most secretive, however, is also the most accidental.

For the original run, Rose Abdoo had played Gypsy, a witty mechanic who kept popping up interacting with a wide range of Stars Hollow’s residents, and while she reprised the role for the follow-up, that wasn’t the only part Abdoo played; as eagle eyed fans spotted, she also donned a curly wig and glasses to play Berta, Emily’s year-long maid.

What does it all mean? Are they estranged sisters or is the show saying something about how Emily views the world? Nothing that complex, actually; as the story goes, Abdoo simply read for Berta at the script read because the part hadn’t been cast yet, and did such a funny take that the showrunners chose to pile on the gags and have her play two roles.

2. Peter Capaldi as Caecilius and The Doctor - Doctor Who

You’ve not really made it as a British thespian if you’ve not appeared on Doctor Who; everyone, from James Corden to Derek Jacobi (and Peter Kay, but we don’t talk about that episode) has played some part in the Time Lord’s adventures. And with so many episodes over so many years, there’s inevitably going to be some actors appearing twice.

There’s countless cases of this in the old series with supporting characters, but it’s more rampant and prolific in the reboot – both Freema Ageyman and Karen Gillan appeared in bit parts before becoming companions in later seasons after, although they’ve nothing on future Doctor Peter Capaldi.

The Thick of It star first appeared in Season 4’s “The Fires of Pompeii” as Caecilius, then as John Frobisher in Torchwood mini-series Children of Earth, before returning five years years later as the Time Lord himself in his twelfth form (technically thirteenth regeneration - look, TV’s confusing). Because Doctor Who’s never above explaining things in the most complicated way possible, this discrepancy was worked into the plot, with the Doctor saying that he takes his new form based on past interactions; he ended up with Caecilius because his actions in Pompeii - saving the sculptor and his family - left such an impact on him.

1. Jeffery Wright as Bernard and Arnold - Westworld

Spoilers for Westworld!

One of the beauties of Westworld is that it can reveal any character is actually a robot and have it make perfect sense; not only are human replicants, called hosts, running rampant in the titular theme park, but the show is directly about consciousness and the nature of our reality. It would be crazy not to have a twist or two.

This is exactly what happened in Episode 7 of Season 1, when a major fan theory was confirmed and it was revealed that Bernard, Jeffery Wright’s head of programming, was actually a host controlled by head honcho Ford (Anthony Hopkins). The rug-pulls didn’t end there though; as any avid theorist had already predicted, in its ninth episode (what is it with HBO and Episode 9 being jaw-droppers?) it was revealed that not only was Bernard a host, but he was a near-perfect replica of Arnold, Ford’s original partner killed at the park’s inception. Bernard’s purpose wasn’t just to be Ford’s laky, but continue his deceased friend’s work. Chilling!