Both Ryan Stiles and Colin Mochrie were regulars on the original Whose Line Is It Anyway? (1988) the Channel 4 (UK) version of the series.
A continuation of Whose Line Is It Anyway? (1998), which was a remake of a British TV show with the same title (Whose Line Is It Anyway? (1988)).
Colin Mochrie is the only performer to be present in every single episode of the show. Ryan Stiles has missed only a few.