Thorne, 17, has been spending more time with Lee, 18, over the past few weeks and now it seems the pair have taken their friendship to the next level, reported E!Online.
"They are seeing each other. But it's in early stages," a source said.
On March 21, both Thorne and Lee posted different pictures of them together on Instagram.
Thorne posted one picture taken during their romantic meal at Nobu restaurant in Los Angeles. She posed with Lee while wearing a beautiful little black dress and captioned it, "Nobu with this one @brandon__lee."