Robert Downey Jr is set to astound fans with his new movie - the reformed hellraiser has signed up to play superhero IRON MAN. The comic book adaptation marks the Oscar nominated actor's first lead role in a big-budget Hollywood action movie. He is best known for appearing in gritty movies including Chaplin, Wonder Boys and Natural Born Killers. Shooting on Iron Man, which is being directed by actor/director Jon Favreau and is the first self-financed movie by Marvel Studios, is scheduled to begin in February 2007.