Charlize Theron Sean Penn gym

After vacationing with Sean Penn in Hawaii and then seemingly spending the night with him on Wednesday, Charlize Theron kept a low profile when she left the gym on Thursday afternoon. While the two have been friends for years, we have to wonder if they're finally taking the next step...

Charlize stayed at Sean's beachfront home in Oahu for the last week, and the two even took the same flight back to the mainland on Wednesday night. On Thursday morning X17 photographers snapped Sean leaving Charlize's Los Angeles home just 12 hours after the two jetted from Hawaii to LAX. Not only that, but a source tells People that the duo were "laughing and touchy-feely," at Seth MacFarlane's holiday party last month.

Still, a source tells the mag that it's nothing serious. "Charlize and Sean have been friends for years. They have been spotted out together several times in the past few years. Even when Charlize was dating Stuart [Townsend]. They both had dinner with Sean several times."

But Stuart isn't in the picture anymore, so...