Extras is a British sitcom about extras working in television, film, and theatre. The series was co-produced by the BBC and HBO, and written and directed by Ricky Gervais and Stephen Merchant, both of whom starred in it. It follows the lives of Andy Millman (Gervais), his friend Maggie Jacobs (Ashley Jensen) and Andy's substandard agent and part-time retail employee Darren Lamb (Merchant) as Millman muddles through life as an anonymous "background performer" who eventually finds success as a B-list sitcom star.

Extras has two series of six episodes each as well as a Christmas Special. The first episode aired in the UK on 21 July 2005 on BBC Two and on 25 September 2005 on HBO in the US. The second series premiered in the UK on BBC Two on 14 September 2006 and began airing in the US on HBO and in Australia on ABC on 14 February 2007. The Christmas Special aired on 27 December 2007 on BBC One and on 16 December 2007 on HBO. Both series are available on DVD and, at various times, through streaming services in the UK and the US.

The series is filmed in a more traditional sitcom style than the mockumentary style used by Gervais and Merchant in their previous series The Office. Each episode has at least one guest star: a television or film celebrity who plays what Gervais and Merchant have referred to as "twisted" versions of themselves—an exaggerated or inverted parody of their public persona. The show has been critically acclaimed, and has a Metacritic score of 81/100.

Andy Millman is an aspiring actor who can only find work as an extra, which he calls being a "background artist" as a means of making the work seem more dignified. Andy is accompanied on his various projects by his platonic best friend and fellow extra, Maggie Jacobs. Maggie is well-meaning but ditzy, often missing obvious social cues and failing to exhibit appropriate tact and subtlety in conversations. Unlike Andy, Maggie has no aspirations toward being anything more than an extra. Andy's agent, Darren Lamb, has no real experience in the field of entertainment. He is incompetent, often taking no steps at all to find work for Andy, and even discouraging potential employers from hiring his client due to his flabby physique, age, and lack of acting experience. Darren is assisted by former soap opera star Shaun Williamson, who plays himself. Lamb frequently tries to undermine Andy by suggesting Williamson (who Lamb refers to by his former EastEnders character name, "Barry") is better suited for various acting roles that are offered to Andy.

Fed up with life as an extra who is always being cut out of scenes just as he manages to get his face on camera, Andy shamelessly kisses up to celebrities and producers in an effort to try to get screen time or a line of dialogue. Although often successful in these endeavours, circumstances always arise that prevent Andy from advancing his career. Reasons include celebrities confessing that they have no real power to help, or (more often) Andy inadvertently offending the star which results in his immediate dismissal from the set. In the conclusion of season one, Andy delivers a sitcom script he has written to Patrick Stewart, who, in turn, passes it along to the BBC through his production company. Andy gets a meeting with BBC comedy producers who greenlight his project and agree to allow him to play the starring role in the show.

Series Two largely chronicles Andy's frustrations with his sitcom—When the Whistle Blows—which is heavily rewritten by BBC producers, resulting in it being a lowest-common-denominator comedy that relies on a multitude of catchphrases, offensive stereotypes and silly costumes for cheap laughs. Although the sitcom is commercially successful, pulling six million weekly viewers, it is a flop with critics who mercilessly bash both it and Andy. Andy periodically gets a chance to expand his repertoire in film and on stage but manages to ruin every opportunity that comes his way by either refusing to take direction, or by once again offending bigger stars than himself.

In the series' 90-minute finale, the sitcom has made Andy financially successful and recognisable to many but he is increasingly frustrated with the show's quality and with his career not moving forward. Andy is convinced to fire Darren as his agent and become a client of a larger, more professional firm which he believes will accelerate his path upward. After taping a Christmas Special for When the Whistle Blows, he announces to the live studio audience that he is quitting the series effective immediately. His career falls into total stagnation and Andy is forced to take bit parts on various long-running British television series such as Doctor Who and Hotel Babylon. Eventually, his agent ceases to take his calls. Andy's relationship with Maggie sours as he frequently ignores her and spends all of the time they spend together complaining about not getting the opportunities he feels he deserves.

When he crashes his agent's lunch meeting at a posh restaurant, he is bluntly told that he will never realise his dreams of having fame, fortune, prestige and respect. Crushed, Andy reluctantly agrees to lower his expectations for the sake of remaining modestly famous and successful and is cast in Celebrity Big Brother. While staying in the Celebrity Big Brother house, Andy openly reflects upon the price of fame and grows increasingly disenchanted with the culture of celebrity worship that has manifested itself throughout Western society.