AceShowbiz -

Sean Penn, 54, and Charlize Theron, 39, are reportedly engaged. While the two stars haven't directly commented on the engagement rumor, a representative for "The Secret Life of Walter Mitty" actor insists it's "all speculation."

According to Us Weekly, the "Milk" star popped the big question to the "Snow White and the Huntsman" actress during a trip to Paris this past November. "There's no ring, but they are committed," a source claims.

The couple first stepped out together in December 2013. If the rumor is true, it will be the third marriage for Penn who was previously married to Madonna and then to Robin Wright. Theron previously dated Irish actor Stuart Townsend. They broke up in 2010 after nine years of dating. She adopted son Jackson two years later.

"I really didn't see it coming," she said of her relationship with Penn. "Sean and I have known each other for 18 years. We were just really good friends. And it's been slow going because you are aware that you could screw that up and lose it. We had to think about it. But at the end of the day, it was somewhat effortless. It just kind of naturally happened, and before I knew it, I was in something that was making my life better - the people who really love me can see the effect it has had on me."