Peter Jackson
Peter Jackson portrayed himself in a cameo for the 50th Anniversary story The Five(ish) Doctors Reboot.
Despite having directed the highly acclaimed The Lord of the Rings and The Hobbit film trilogies, he can also be seen in a cameo role as a violent Santa Claus in the Edgar Wright and Simon Pegg film, Hot Fuzz.
Jackson has admitted himself to be a die-hard fan of Doctor Who, owns two classic Daleks, and has even expressed his interest in directing an episode of the series; “They don’t even have to pay me ... But I have got my eye on one of those nice new gold-colored Daleks. They must have a spare one (hint, hint).” [1] Despite his reluctance to work outside of New Zealand, and his inexperience of working within Television, he has stated that discussions are "actually kind of serious".[2]