Leighton Meester and Garrett Hedlund'Country Strong' co-stars Leighton Meester and Garrett Hedlund may be taking their on-screen romance off-screen as well.

At HBO's Golden Globe after-party, UsMagazine.com reports the pair were "inseparable the entire night."

"Garrett wrapped his arm around her," a source said. "She wrapped her arm completely around his neck and pulled him in for a quick peck on the lips."

When the pair left the party, they exited together -- with Hedlund seen massaging Meester's shoulders.

Meester split from 'Gossip Girl' co-star Sebastian Stan last year.