Leighton Meester (Blair Waldorf) and Kristen Bell (Gossip Girl) never shared screentime on Gossip Girl — but they did sit a couple desks away from one another for two episodes of Veronica Mars in 2005. In this clip, Leighton plays a student accusing her teacher of having an affair with her. Considering the teacher is played by Adam Scott, well, we wouldn't have blamed her if it were true.
Later in the episode, Kristen confronts Leigh about the truth of her accusation, and eventually focuses on taking her down. Based on this, we wish that Kristen had spent a lot more time interacting with Blair on GG. Can you imagine what a sleuthing team they would have made? Check it out.