Colin Mochrie is an actor, writer, producer and improvisational comedian, most well known for his appearances on the TV show, Whose Line Is It Anyway? He was featured in the British version hosted by Clive Anderson, as well as in the American version hosted by Drew Carey on ABC. He's been on Whose Line Is It Anyway? since 1991. Colin Mochrie has been making people laugh for the last 30 years and he's one of our favorite improv comedians out there. Ryan Stiles is another actor/comedian on the show and he and Colin Mochrie are best friends. They also happen to be the only two performers to appear in every episode. Eytan Millstone video.