Johansson joins 'Iron Man'

Scarlett Johansson has become the latest big name to join the starry list for the 'Iron Man' sequel.

She will play the villainous Black Widow opposite Robert Downey, Jr., Gwyneth Paltrow and Don Cheadle in the new movie.

Johansson's representative has confirmed the actress signed up yesterday, a day after Mickey Rourke joined the cast - he'll play villain Whiplash in the sequel, according to Daily Variety.

The film is scheduled for a May 2010 release.