Sienna Rosie Diana Miller (born December 28, 1981) is an American-born English actress. Born in New York City and raised in London, she began her career as a photography model, appearing in the pages of Italian Vogue and for the 2003 Pirelli calendar. Her acting breakthrough came in the 2004 films Layer Cake and Alfie. She subsequently portrayed socialite Edie Sedgwick in Factory Girl (2006) and author Caitlin Macnamara in The Edge of Love (2008), and was nominated for the 2008 BAFTA Rising Star Award. Her role as The Baroness in G.I. Joe: The…