It looks like Miley Cyrus and Liam Hemsworth are more than just friendly costars.

Last Wednesday, as Cyrus bid Australian actor Liam Hemsworth goodbye at the Nashville airport, the two kissed – and were "full-on making out," says Alex Emanuel, a New York actor who was a few feet away from the couple and saw Cyrus, 16, act "as giddy as a schoolgirl."

Hemsworth jumped out of Cyrus's truck with his luggage and headed for the terminal doors when "she jumped into his arms and threw her arms around his neck and kissed him and leaned back and he was dipping her," says Emanuel. "It was like a scene out of an old movie where the guy's getting on a train and they're saying their goodbyes."

The two actors recently wrapped the film The Last Song (also starring Kelly Preston and Greg Kinnear) in Tybee, Georgia, and attended the film's wrap party together on Aug. 16.

According to Cyrus' Twitter posts, she is maintaining her single status. "I do not have a boyfriend," she writes.

But she says shhe's been teaching Hemsworth a thing or two about Southern eats. "@mommytish and @auntedi and I are introducing the aussie to cracker barrel!!! Yummyyy :)" Cyrus wrote about taking Hemsworth to the restaurant chain.

She also revealed they like to stay in and nosh in front of the TV. Her Aug. 14th Tweet: "I kinda want to go see 'The Time Traveler's Wife' but I think I'll just sit around and eat sushi and watch "Liar Liar" with Liam :)"

Cyrus' publicist had no comment.