Sienna Miller was back in NYC walking her dog yesterday after her quick trip to England for London Fashion Week. She's in the states to resume her run in After Miss Julie, but the stylish times in the UK are continuing with other stars like Gwyneth, Freida, and Posh. Sienna recently opened up about her latest Twenty8Twelve collection and its inspiration, saying, "London girls are really at the forefront, I think my biggest inspiration. . . was driving through London. People really aren't afraid to be themselves." It's time for Sienna to switch gears from designing back to acting, as she focuses on the stage for her play's seven-week run.