In 2005, Miller played the female lead opposite Heath Ledger in the period comedy drama, Casanova, followed by the role of 1960s socialite and Andy Warhol's muse Edie Sedgwick in Factory Girl, which opened 29 December 2006.In 2007, Miller had a small role in Matthew Vaughn's adaptation Stardust and played a starlet to Steve Buscemi's reporter in Interview, another remake. She appeared in the film Hippie Hippie Shake, a Working Title production which starred Cillian Murphy, completed in 2009 but unreleased as of December 2016, and played the title role in Patrick Marber's After Miss Julie on Broadway.

The actress, who shares daughter Marlowe, 4, with ex Tom Sturridge, hasn't been shy about showing PDA with Bennett.In 2006 it was announced that Miller would design a fashion capsule for Pepe Jeans; the project was later expanded to become a complete fashion label.on Sunday (September 11) at the USTA Billie Jean King National Tennis Center in New York City., and it seems the pair have made quite the impression on one another. Spotted together at Wimbledon on two seperate occassions, the ex-colleagues could be seen cuddling up, with Sienna resting her head on the handsome Bennett's shoulder as they watched a game.