We didn't catch Conan O'Brien last night because at the time it aired we were at a Nylon party with Blake Lively and Penn Badgley from Gossip Girl, craning our necks to see if we could catch them smooching. (We didn't.) But today we managed to find the above clip of their co-star Leighton Meester giving her debut performance on the show. Despite our deep abiding love for Leighton/Blair, we were not terribly impressed. She basically spends the entire segment giggling, which eventually even makes Conan nervous. It's like she's become the anti-Blair. This is not what she seems to be like in real life, so the poor girl must have been very nervous. You really have to watch it. For a while we were convinced it was actually Rachel Bilson onstage and someone at NBC had made a terrible mistake.

Conan the Barbarian Pervs on 'Gossip Girl' [BlackBook]