Buzz: Charlize Theron, Sean Penn break up

This Hollywood power couple may be no more.

According to E! News and Us Weekly, Sean Penn, 54, and Charlize Theron, 39, have split after a year and a half together.

That makes their glam red carpet walk at the Cannes Film Festival in May the couple's last public appearance together.

The two had just begun to open up about each other to the media. "You say I've been married twice before, but I've been married under circumstances where I was less informed than I am today," Penn told Esquire UK in March, speaking of his future with Theron. "So I wouldn't even consider it a third marriage, I'd consider it a first marriage on its own terms if I got married again. I mean, I like the tradition. A friend of mine wrote a line, 'Without tradition, new things die.' And I don't want new things to die."

He added that he felt lucky to fall in love in his fifties. "53 years old plus finally beginning to figure out why you haven't been happy in a single relationship? It could seem too late. But to run into somebody now who you care about is a much more passionate, deeper, truer and – God! – a much happier feeling. It's a lot more romantic and a lot more fulfilling to be in a relationship and to think you're a good person within it."

In May, Theron told Esquire the relationship had taken the friends of 20 years by surprise. "I'm a very, very, very lucky girl. Very lucky. He's hot. He is hot. How do you say that in an interview? You're a forty-year-old woman sounding like a sixteen-year-old. There's something beautiful about that, but you lack the articulation of really saying what it's like when somebody walks into your life and makes you see something that you really never thought you'd be able to see. If somebody had said to me, 'This is what it will be,' I would've said, '(expletive) off.' As you can see, it makes me smile."

Charlize Theron recently lit the box office on fire with Mad Max: Fury Road, while Penn saw a disappointing open for his international shoot 'em up, The Gunman in March. Theron is mom to 3-year-old Jackson, whom she adopted in March 2012. Penn has two grown children from his marriage to Robin Wright, Dylan and Hopper.

If true, the split may prove to be awkward for the exes later this year: Penn is currently finishing editing his next directorial effort, The Last Face, which stars Theron. In March, he told USA TODAY she's "a director's dream."