Ricky Gervais (in-universe)

Ricky Gervais was a human celebrity. In 2004, he attended the opening of the Tomorrow Windows at Tate Modern. (PROSE: The Tomorrow Windows)

In the real world
Gervais is one of the writers of the popular TV series Extras. The main character, Andy Millman (also played by Gervais), starred as a slug-like alien who faced the Tenth Doctor and an unnamed companion in a non-canon episode of Doctor Who as part of a scene in an episode of Extras.