'Whose Line Is It Anyway?' is an improvisational comedy show consisting of a panel of stand-up comedians who create characters, scenes and songs based on a topic given to them by host Clive Anderson. Regular performers include John Sessions, Paul Merton, Josie Lawrence, Sandi Toksvig, Greg Proops, Ryan Stiles, Colin Mochrie, Tony Slattery, Mike McShane, Stephen Frost and Jim Sweeney. The winner of each episode is chosen by Clive and the prize is to read the scrolling closing credits in a style chosen by the host. A hugely successful American version features Drew Carey as the host, with the performers including Stiles, Mochrie and Wayne Brady. The UK version premiered on Channel 4 in 1988 and ran for 136 episodes. The US version made its debut in 1998 and clocked up 220 editions.