Whose Line Is It Anyway? is a short-form improvisational comedy show created by Dan Patterson and Mark Leveson. The three major versions of the show are the original 1988 British radio programme (from which all subsequent versions are adapted), the British television programme, which ran from 1988 to 1999, and the American television programme, which ran from 1998 to 2007 and was revived in 2013. All three versions were produced by Patterson and Leveson and have a continuity of cast (for example, both the British radio and television shows were hosted by Clive Anderson, while several performers from the British television show then starred in the American television show).

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Each version of the show consists of a panel of four performers who create characters, scenes, and songs on the spot, in the style of short-form improvisation games, many taken from theatresports. Topics for the games are based on either audience suggestions or predetermined prompts from the host. The show ostensibly takes the form of a game show, with the host arbitrarily assigning points and likewise choosing a winner at the end of each episode.