Leighton Meester looks beautiful in blue as she celebrates Fashion’s Night Out at Tiffany & Co. on 5th Avenue on Thursday (September 8) in Manhattan, NY.

The 25-year-old Gossip Girl star wore a dreamy blue floor-length dress to the store, where she held a special live acoustic performance for guests.

Earlier in the week, Leighton hinted on Twitter what songs she was going to perform for the FNO event.

Leighton tweeted, “4 acoustic songs, 2-3 guitars + special intro cover song!”

P.S. The special intro cover song Leighton performed was Pink Floyd‘s “Shine On You Crazy Diamond.”