Kristen Stewart and boyfriend Robert Pattinson celebrated her London premiere of Snow White and the Huntsman last night at the city's Quo Vadis restaurant. They were seen leaving the spot late in the evening. Kristen wore a see-through Marchesa to the screening, but changed into her trademark t-shirt, jeans, and leather jacket for the partying. Robert and Kristen are back in London following a weekend away. Robert and Kristen were in West Sussex for a few days, since she was busy doing press at Arundel Castle nearby. It also gave the couple a chance to have a romantic getaway in honor of Robert's 26th birthday Sunday.