Leighton Meester cheered on ex-boyfriend Sebastian Stan as he picked up the award for Best Actor, Musical or Comedy at the 2025 Golden Globes Jan. 5. The Gossip Girl costars dated from 2008 to 2010. Hey, Upper East Siders, Sebastian Stan and Leighton Meester are serving you with some relationship nostalgia. The Gossip Girl costars, who dated from 2008 to 2010, were one of the many former couples to reunite at…