A source told Celebuzz.com, "They stayed around two to three hours and Nina left before Liam, and as she was leaving they gave each other a good night kiss... (and) she ran off into a car service with her friend."
The pair are both working on the East Coast. Dobrev, 25, is filming the fifth season of her popular CW show, while Hemsworth, 24, is working on "The Hunger Games: Mockingjay - Parts 1 and 2."
The actor was famously engaged to singer/actress Miley Cyrus before splitting up with her last year.
Dobrev dated her "Vampire Diaries" co-star Ian Somerhalder from 2010-13. She also briefly dated "Dancing With The Stars" pro Derek Hough.