The Gossip Girl costars, who dated from 2008 to 2010, were one of the many former couples to reunite at the 2025 Golden Globes on Jan. 5, with Leighton cheering on her ex as he picked up the award for Best Actor in a Motion Picture—Musical or Comedy trophy for his role in A Different Man.
When Sebastian, 42, was announced as the winner—beating out fellow nominees Jesse Eisenberg (A Real Pain), Hugh Grant (Heretic), Gabriel LaBelle (Saturday Night), Jesse Plemons (Kinds of Kindness) and Glen Powell(Hit Man)—Leighton, 38, could be seen smiling and giving him a huge round of applause.
And while the former couple have each moved on in the 14 years since their breakup—Leighton and husband of 10 years Adam Brodyare parents of two whileSebastian has been dating actress Annabelle Wallis since 2022—the duo have been candid about their former romance.
As Sebastian shared in September, his role as Carter Braizen on Gossip Girl from 2007 to 2011 was particularly significant for him because it coincided with an important relationship in his life.
"It was the first time I was in serious love with somebody," he told Variety, without naming the Single Parents alum. "Walking around the city, seeing these same buildings and streets—life seemed simpler."
As for Leighton—who was at the Golden Globes supporting her nominated husband—she has mostly kept mum about their romance, although she has discussed how difficult their breakup was.
"I've only had one experience where it was really hard and I was really sad when it ended," she told Marie Claire in 2012, "but that's what taught me a lot about myself and love and life—and that's good."
To see more unforgettable moments from the 2025 Golden Globes, keep reading.