In the 2005 film version of Charlie and the Chocolate Factory, he portrayed all of the Oompa-Loompas. He also plays the alien Keenser in the 2009 film Star Trek and its 2013 sequel, Star Trek Into Darkness.
To sci-fi fans, he is best known for his role as Mr. Sin in the Doctor Who serial Talons of Weng-Chiang as well as the Posicarian delegate in the later serial Mindwarp. He was the only actor to appear in the Star Wars, Star Trek and Doctor Who franchises, until Simon Pegg's appearance in Star Wars: The Clone Wars.