8. Jon Favreau
Despite having written and starred in the 1996 classic Swingers, Jon Favreau never really became a recognisable name as an actor, with highlights including a six episode stint on Friends and a guest appearance on The Sopranos. Moving into directing, he made three films (including Elf) in a four year period in the early 2000s, catching the eye of Marvel Studios, who offered him the director's chair for Iron Man, turning a secondary comic character into a blockbuster hit, and paving the way for the development of several other Marvel properties. Having directed the film's sequel, Iron Man 2, in 2010, Favreau has stepped down for the upcoming Iron Man 3, which will be helmed instead by Shane Black, but his stock is still soaring, as he prepares to work on a new Disney Studios film