PHOTOS: Taylor Momsen Welcomes You to the Grin Show

Is that...? Could it be...? no way! Taylor Momsen is SMILING! The oft-pantless one broke out a big grin in NYC yesterday, heading to her trailer on the set of Gossip Girl. Even a huge run in her tights couldn't keep her smile at bay — and the 16-year-old's skirt was almost to her knees! Progress, T-Mom, progress!