Sienna Miller is a Real American Hero

Sienna Miller leaves her North London home on Thursday, dressed in head-to-toe black-and white.

Maybe preparing for her villainous role as a raven-haired baroness and sexy femme fatale in the G.I. Joe movie?? Cannot wait to see her suited up for that one. Baronesses do not wear baggy!

The Hollywood Reporter is also reporting that three other actors are joining Sienna and Ray Park in G.I. Joe: Rachel Nichols (Alias), Adewale Akinnuoye-Agbaje (Lost) and Said Taghmaoui (The Kite Runner). EXCITING!