Robert Downey Jr. is to reteam with Jon Favreau on his next movie venture.

The 'Iron Man' actor and director have signed up for sci-fi western 'Cowboys and Aliens', which is based on a graphic novel by Fred Van Lente and Andrew Foley.

The movie centres around a battle between Apaches and western settlers which is disrupted when an alien spaceship crash lands. Robert - who is currently working on 'Sherlock Holmes' - entered talks to star in the DreamWorks project last year, but his involvement has only just been confirmed, while Jon has only now signed on for the movie, which is expected to be his next project immediately after finishing 'Iron Man 2'.

'Iron Man' writers Mark Fergus and Hawk Ostby were working on the project but have now been replaced by screenwriters Alex Kurtzman and Roberto Orci and 'Lost' producer Damon Lindelof. 'Cowboys and Aliens' is scheduled for release in 2011.