Sienna fights GI Joe

The big-screen G.I. JOE movie is getting locked and loaded, with cast already joining the production. And they’re starting with the bad guys. Or girls.

Sienna Miller gives new meaning to the term “living doll” — she’s the first official human to join the Stephen Sommers-directed modern war flick based on Hasbro’s megapopular action figure line. The British model/actress/sexpot will slink into black form-fitting attire (and wig or dye job) as the villain Baroness, the right-hand woman of Cobra Commander. Expect a potentially arousing catfight with Scarlett to occur a some point in the film’s runtime.

The movie is still planned for a February start (and Aug. 7, 2009 release date), so more cast should be announced soon. The story, as if you didn’t know, involves a diverse group of specially trained soldiers battling an international terrorist organization called COBRA.