Jamie Campbell Bower (born 22 November 1988) is an English actor. He is arguably best-known for his role as Caius in The Twilight Saga: New Moon and as Number 11-12 in The Prisoner. He will be playing Gellert Grindelwald in the final two Harry Potter films.In Game of Thrones Campbell Bower was supposed to be playing Ser Waymar Royce. He was confirmed in the role on 20 October 2009, and played in the unaired pilot episode. However, he was replaced by Rob Ostlere for the series proper. Campbell Bower has gone on to play King Arthur in the drama series Camelot.