More Photos17 Nicole Richie stepped out in a gorg Miu Miu dress for last night's Prada screening of their animated short film, Trembled Blossoms, but earlier in the day she rocked her best school girl look to attend driving classes in Los Angeles. Stemming from her December 2006 DUI, Nicole has already taken several sessions and must be nearing the end of her required driver's education course. To celebrate, the new mom schmoozed with stylish stars like Prada-clad Rosario Dawson, Angie Harmon and Miu Miu wearing Brooke Shields and Michelle Trachtenberg. It's also been a big day for Michelle since TV Guide announced that the former Buffy the Vampire Slayer kid sis nabbed a much coveted, and decidedly more grown up, role as a Park Avenue vixen on Gossip Girl!