Simon Pegg has ruled out an appearance in British TV show Doctor Who - because he is such a big fan of the show. The Hot Fuzz star appeared in an episode of the sci-fi series in 2005, but will not audition for the lead role of the Doctor following the departure of David Tennant, because excitement would overrule his acting skills. He says, "I'm too much of a fan to actually play the doctor. I think my head would actually explode.