The show Whose Line Is It Anyway? originally ran for 8 seasons from 1999-2008. Each episode had 4 comedians doing improv. Two of them were always Collin Mocherie and Ryan Stiles, of the other two, it seemed like Wayne Brady was on at least 80% of the time and then for the other comedian there was an alternating guest slot which rotated between different repeating guest stars. But on the times when Wayne Brady wasn't on, there would be two alternate guest stars.

So I'm wondering what exactly was Wayne's official status on the show? Was he a co-star or a guest artist? He definitely seemed like more than just a slot filler for the alternating guests, and arguably was an intricate part of why the show was so successful with his amazing ability to improv musical styles.