5. Terry Gilliam
Initially finding fame as one of the six members of Monty Python, serving as both animator and actor for the comedy group, Gilliam quickly moved into live action directing upon the conclusion of the series in 1974, taking the director's chair, alongside Terry Jones, for the group's first feature film, Monty Python And The Holy Grail, in 1975. This was followed in 1977 by Jabberwocky, which though largely unremembered, paved the way for greats of the sci-fi and fantasy genre such as Time Bandits (1981), Brazil (1985) and Twelve Monkeys (1995), and led to him being the favoured choice of J.K Rowling to direct the first movie in the Harry Potter franchise, an honour that eventually went to Chris Columbus at the insistence of Warner Bros. Now 71, Gilliam shows no signs of retiring in his old age, currently filming his latest project, The Zero Theorem, with Christoph Waltz and Matt Damon set to star.