Iron Man 2, the sequel to the hit 2008 film Iron Man – starring Robert Downey, Jr., in the lead role – will have Scarlett Johansson as the Russian spy Black Widow. Johansson had to undergo a tough workout regimen and a low-carb diet just to be able to fit into the Black Widow character’s tight, revealing outfit. What hasn’t been revealed is whether Black Widow is a villainess or heroine.

Also in the cast of Iron Man 2: Don Cheadle (Col. Rhodes), Gwyneth Paltrow (Pepper Pots), Mickey Rourke (Whiplash), Sam Rockwell (Justin Hammer), Samuel L. Jackson (Nick Fury), and even director Jon Favreau (Hogan). Johansson replaced Emily Blount as Natasha Romanoff/ Black Widow.

The sequel opens early May, 2010, and will have Jon Favreau back in the Director’s chair. Favreau recently confirmed at Comic-Con 2009 that there will be an Iron Man 3.