In the same 2008 episode of Doctor Who in which Peter Capaldi made his first appearance in a different role, future Marvel movie star Karen Gillan also made her debut on the cult favorite series as a soothsayer who gained psychic powers from breathing in dust from the volcano, Vesuvius. Two years later, the Scottish actress was cast as Amy Pond, who would accompany Matt Smith as the Eleventh Doctor on adventures until 2012.

Before he joined the Friends cast in the recurring role of Frank Buffay Jr. - the younger half-brother of Phoebe (Lisa Kudrow) - Emmy nominee Giovanni Ribisi made an uncredited Season 2 appearance as a guy who asks if he can retrieve the condom he dropped in Phoebe’s guitar case moments earlier. Considering Phoebe never found out about this sibling until later that season, fans have speculated that Frank and “Condom Guy” are the same person, but this has never been confirmed.

Before she was in the Living Single cast, future Academy Award nominee Queen Latifah shared the screen with fellow rapper-turned-actor Will Smith on two episodes of The Fresh Prince of Bel-Air in 1991. She played a vain, domineering actress who hires Hilary (Karyn Parsons) as an assistant for her first appearance, and returned to play a woman whose friendship with Will is tested when he does not defend her from ridicule about her weight.

The late, great Jerry Orbach of Dirty Dancing fame is even better known for his 12 seasons in the Law & Order cast as Detective Lennie Briscoe, for which he received his third Emmy nomination. However, his first appearance on the long-running crime procedural (which was revived in 2022) was in Season 2 (a year before he official joined the cast) as Frank Lehrman - a lawyer defending a woman who shot her estranged husband and his mistress. 

On the premiere season of Sex and the City, Justin Theroux appeared as Jared - Carrie Bradshaw’s (Sarah Jessica Parker) post-Mr. Big rebound - before showing up again the following season as Vaughn Wysel -  Carrie’s writer boyfriend whose stories are short, just like his bedroom stamina. The star of HBO’s The Leftovers explained on an episode of People Magazine’s Couch Surfing how he prepared for his second role on the iconic romantic-comedy series by shaving his head.

It is not so unusual for a Game of Thrones cast member to die and come back later (i.e. Kit Harrington’s Jon Snow), but Dean-Charles Chapman is a special case. The 1917 star appeared in two episodes of the third season as a Lannister House squire named Martyn before being brought back the next year (and with a sweet promotion) as the polarizing King of the Andals, Tommen Baratheon.

Because of Time Lords’ regenerative process, the titular hero of the phenomenal British sci-fi series, Doctor Who, has been played by 13 different actors so far - including Oscar-winner Peter Capaldi (who looked to David Bowie for inspiration for the role) from 2013 to 2017. However, die-hard Whovians may recall when the Scotsman appeared opposite the Tenth Doctor, David Tenant, in 2008 as a man The Doctor saves from Vesuvius’ eruption named Caecilius.

On Married… with Children (which some believe is due for a revival), the Bundy Family’s next-door neighbor, Marcy (Amanda Bearse), was married twice - the second time to Jefferson D’Arcy, who was played by Ted McGinley after he joined the cast in Season 5. The previous season, he appeared in a holiday episode inspired by It’s a Wonderful Life in which Al (Ed O’Neill) is shown an alternate reality where Peg (Katey Segal) is, instead, married to a more successful, better looking man named Norman Jablonsky (McGinley). 

Emmy winner Terry O’Quinn, best known from the Lost cast, has starred in a number of series created by Chris Carter - including one of the best ’90 shows, The X-Files, as both a police lieutenant in Season 2  and a super-soldier who tries to kill Scully (Gillian Anderson) in Season 9. He was also a regular on another supernatural series by Carter called Millennium, which once crossed over with The X-Files - meaning O’Quinn has really played three characters within this same universe.

Garett Dillahunt is one of the few names on our list who, instead of just two guest appearances, can claim to have two different, multi-episode recurring roles in the Deadwood cast. He played the crooked-nosed murderer Jack McCall in the HBO series’ first season, before returning in Season 2 as geologist Francis Wolcott. He even made an uncredited cameo in the series’ feature-length continuation from 2019 as random drunk.

Emmy winner S. Epatha Merkerson, who went on to be a staple of the One Chicago franchise, is best known for playing Lt. Anita Van Buren on Law & Order from 1993 to 2010. Yet, her first role on the iconic crime drama was as the mother of two young shooting victims in the the series’ premiere season.

During Paget Brewster’s temporary absence from the Criminal Minds cast, she had a starring role on Community as Frankie Dart - a consultant hired to help improve things on the Greendale campus. There is a clever joke from Season 6 of creator Dan Harmon’s cult favorite comedy when Frankie claims to have some bizarre trouble when trying to reach out to Greendale’s I.T. department head, Debra Chambers - whom Brewster also played in the previous season.

The producers of Barney Miller (one of funniest and best classic mystery shows) cast several actors in multiple guest appearances over its eight seasons, including Oscar nominee James Cromwell. He first appeared as a police sergeant in 1977, a representative of the department of energy two years later, and both a corporate representative and stress researcher in 1981.

Years before appearing on the hit HBO comedy Insecure or FX’s acclaimed crime drama Snowfall, Denise Dowse appeared on a total of 24 episodes as part of the Beverly Hills, 90210 cast from 1990 to 2000. In 23 of those episodes, she played West Beverly Hills High School vice principal Yvonne Teasley, and also played a college professor in an episode of Season 1, which was also her first.

Diane Neal has starred on the crime procedural spin-off Law & Order: Special Victims Unit (initially as a regular and later in recurring and guest appearances) as Casey Novak - an assistant district attorney who also appeared in an episode of the short-lived Law & Order: Trial By Jury. The actress has actually played two characters in this universe - the first being a stockbroker convicted of the murder of a male stripper on SVU’s third season.

Before joining the New Amsterdam cast and starring in The Matrix Revolutions, Freema Agyeman first appeared with the Doctor Who cast as Torchwood technician Adeloa Oshodi in 2006. The following year, she was cast as Martha Jones - a companion to David Tenant’s Tenth Doctor - who was later revealed to be Adeloa’s cousin to explain the resemblance between the two.

If her starring roles on The Drew Carey Show, with the Scrubs cast, and on Cougar Town do not earn Christa Miller the right to be called sitcom royalty, how about her two disparate guest roles on one of the most celebrated sitcoms of all time, Seinfeld? Miller contributes to two memorable George Costanza moments - the first being when she cost Jason Alexander’s iconic character a bra salesman position after a disastrous attempt at hitting on her in Season 5. In Season 6, she played a woman already dating George, but her unflattering doodle of him suddenly makes him unsure if her affection is genuine.

Comedian and Being the Ricardos star Nelson Franklin is known for having notable recurring roles on a number of sitcoms, including with The Office cast as Dunder Mifflin-Sabre’s begrudgingly overlooked IT guy, Nick, in Season 6. Two seasons earlier, he appeared in the episode “Job Fair” as a graphic design expert whom Pam (Jenna Fischer) approaches with interest in the field.

Before his older brother, James Gunn, cast him in multiple roles in the Guardians of the Galaxy movies (namely Kraglin and Rocket Raccoon, for whom he performed the mo-cap), Sean Gunn play two different characters in the first season of the David Boreanaz-led Buffy spin-off, Angel. The future Gilmore Girls cast member first played a spa manager helping an inter-dimensional demon princess hide other women of her kind from the males who enslave them, before returning a few episodes later as a demon himself - specifically the kind that Angel’s ally, Allen Doyle (Glenn Quinn), is a descendent of on his father’s side.

Years before joining the Yellowstone cast as Steve Hendon, one of James Jordan’s first major TV characters was Tim Foyle - a rival of Kristen Bell’s titular hero from the Veronica Mars cast who appeared in seven episodes, including the 2019 revival season. However, Jordan actually starred in a total of 10 episodes of the hit mystery drama and, for his first three, played a Neptune High janitor ironically named Lucky, who was shot and killed by a school security guard after showing up with an unloaded gun after he was fired.

Earlier in his career, former The Walking Dead cast member Michael Cudlitz made a guest appearance on each of the first three editions of the CSI franchise (and each time as a different character, too), but the original is the only one on which he appeared twice. His first played a cop driven to crime by greed in Season 2, and later played a contractor driven to murder by love in Season 9.