[Selena Gomez] [Kate Mara via Vogue] [Katy Perry, Allison Williams] [Kelly Ripa via BFA]

Fashion's A-listers gathered together last night for The 2012 UNICEF Snowflake Ball, putting on their black-tie best for a philanthropic cause. Meanwhile, guests including Miranda Kerr and Hilary Rhoda were more dressed down at the Footwear News Achievement Awards at the Museum Of Modern Art. And further uptown, Monique Lhullier was busy celebrating her UES flagship store opening with some of her closest fashionable friends. Click through to see our favorite looks from last night.