But at this point, do they even need to?
There certainly weren't any doubts about their off-camera romance this weekend when they took in Friday night's Black Eyed Peas concert at the RBC Center in Raleigh, N.C. (that's where the CW series is shot). An eyewitness gives us the lowdown...
"They were holding hands and touching during the entire show," our source reports. "Austin was standing behind her while she was dancing and singing along."
Joining them for the concert was castmate Lee Norris. "Sophia and Austin were very affectionate," the source continues. "She seemed very happy and very in love."
The good times rolled over to the concert afterparty at local hot spot Tantra, where the One Tree Hill-ers hung out with the Peas in the Bacardi VIP area.
Asked if she could see them getting married someday, Harris tweeted, "I'd be happy if they did."
Don't forget to check out today's Gossip Guru videoblog.