The first series follows Andy Millman (Ricky Gervais) and his friend Maggie Jacobs (Ashley Jensen) as they work as extras and minor characters on film and in theatre. Darren Lamb (Stephen Merchant) is Andy's substandard agent, who fails to procure Andy substantial roles.

Most episodes in the first series are based around a different production in which Andy and Maggie are appearing, with the celebrity guest star usually playing the star of the show. Andy tends to spend a lot of his time looking for ways to get a speaking role, while Maggie is more content with looking among the cast and crew for a boyfriend. At the end of the first series Andy successfully pitches his sitcom, When the Whistle Blows, to the BBC.

The second series focuses on Andy's continuing attempts to be taken more seriously as an actor starring in his sitcom, while struggling with having sold out his vision for the show.

Most episodes in the second series begin with a cold open on a short segment from the production on which Andy and Maggie are working, followed by a fade into the white Extras logo on a black background without an opening credits theme tune. Each episode ends with Cat Stevens' "Tea for the Tillerman" over the closing credits, a track from Tea for the Tillerman of the same name.

• Extras at BBC Comedy
• Extras at HBO
• Extras at RickyGervais.com
• Extras: Season 2 Reviews at Metacritic