The 'Hunger Games' star, who split from fiance Miley Cyrus last year, was seen in the Corner Tavern in Atlanta on February 7 with her, reported Contactmusic.
The duo also shared a kiss before leaving the venue.
"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 kisses were on the lips publicly outside of the bar ... And it was three sensual kisses on the lips. They stuck together pretty much the whole time, but I think Nina got sick of pictures (with fans) because Liam was the highlight, so to speak," a source said.