Leighton Meester and boyfriend Sebastian Stan were side by side as they arrived together at a benefit for the NYC Public Library last night. The duo doesn't appear in public together often, but we've see a great deal of them both this season on Gossip Girl. Sebastian's character Carter is off the series for now, so he wasn't on last night's WTF moment-filled episode, though it did feature the usual tech, fashion, and beauty fun. Leighton has been busy off screen focusing on her music, including her weekend fun onstage with Weezer, and we'll soon get to see the video for her crowd-pleasing first single when it comes out next week.