Leighton Meester is Jimmy Fallon Fierce

Gossip Girl sweetheart Leighton Meester (in Calvin Klein) cozies up to boyfriend and costar Sebastian Stan at the Parsons Fashion Benefit 2009 pre-party at Calvin Klein Collection on Thursday (April 2) in New York City.

Earlier in the day, the 22-year-old actress (in Matthew Williamson) taped her appearance of Late Night With Jimmy Fallon at the Studio 6B in the 30 Rockefeller Center. You can watch her appearance on NBC.com.

10+ pictures inside of Jimmy Fallon fierce Leighton Meester…