When a megastar single mum met a Hollywood heartbreaker...

This remarkable mum reveals how she fell in love with one of Hollywood’s most notorious bad boys.

She’s the proud parent who adopted when she found herself single after a long love affair. And he’s the recent divorcee who counts Madonna and Scarlett Johansson as exes. But now Charlize Theron and Sean Penn are one of Hollywood’s most powerful couples. 

Charlize, 38, has revealed she never expected to fall in love with Sean, who she has known for 18 years.

“It just kind of naturally happened … We were just really good friends,” the South African-born actress told Vogue magazine. “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.”

The Prometheus star has been happily single and enjoying motherhood for the past few years, having adopted her son Jackson in 2012. She says her relationship with 53-year-old Sean was "somewhat effortless".

"It's been slow going because you are aware that you could screw that up and lose it. We had to think about it," she said.

"I know so well what I want to fit in my life. And the simple answer to that is: Unless he can make my life better? My life is really pretty f****** good ... A friend kind of stepped into that role, and I really didn’t see it coming."

Charlize and Sean have looked extremely in love at their recent public appearances, but don't expect them to exchange vows any time soon. Charlize is not a fan of weddings.

"Let's put it this way: I never had the dream of the white dress," Charlize says.

"And watching other people getting married? I think it's beautiful for them, but to be quite honest, usually I'm sitting there just devastated. It's supposed to be this night of celebrating love, and all you see is a couple separated all night making sure everybody else is okay. It just looks like a lot of work."

Sean, who most recently appeared in The Secret Life of Walter Mitty, has previously been married to Madonna and House of Cards star Robin Wright, with whom he has two children. Charlize has never been married, but was in a nine-year relationship with actor Stuart Townsend.

She says that adopting her son Jackson fulfilled a long-held dream for her.

“Even in my relationship with Stuart, that was something I was very clear about,” Theron told Vogue about her desire to adopt. “We had very different ideas of what a family looked like. There’s no judgment; that was not the reason why we broke up, but when we did, adopting was not a last resort for me—it was almost like a first resort. And it’s the only thing in my life that’s surpassed how great I thought it would be.”