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, 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.