Peter Jackson
Peter Jackson portrayed himself in a cameo for the 50th Anniversary story The Five(ish) Doctors Reboot.
Jackson is an award winning feature film director, best known for the highly acclaimed The Lord of the Rings and The Hobbit film trilogies. He can also be seen in cameo roles in most of his films, as well as 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] It has since been stated that discussions are "actually kind of serious".[2]
Jackson also helped to found Weta, a design and special effects company which, in 2010, designed the Eighth Doctor's wooden-handled sonic screwdriver. [3]