Josh Harnett and girlfriend Tamsin Egerton are expecting a baby Credit: Michael Kovac/Getty Images

Josh Hartnett's going to be a dad! The Black Hawk Down star, 36, and his 26-year-old girlfriend Tamsin Egerton are expecting a baby, the actor's rep confirmed to Page Six.

"It's true and they are beyond thrilled," the star's rep confirmed to the outlet.

Hartnett met British actress Egerton in 2011 on the set of The Lovers, but they didn't start dating until much later. As Us Weekly previously reported, they were first spotted stepping out together in May 2013, both in New York City's SoHo neighborhood, and a fortnight later in Dublin, Ireland, when Hartnett traveled to visit his girlfriend while she filmed her movie Love, Rosie.

The couple's friendship developed into a romance very gradually. "It was just a natural thing that happened," a source told Us at the time. "He said she was really nice. They seem to just really enjoy each other's company. And he thinks she's gorgeous, of course."

Hartnett has quite a reputation for dating costars. Prior to Egerton, the handsome star dated Julia Stiles, Kirsten Dunst, and Scarlett Johansson, all of whom he worked with on movies.

"I think it’s a respectable way of going about it,” the actor told Playboy back in April. "I’ve met very important people in my life doing films. Sometimes that had consequences that were just awful for everybody involved. Some were fantastic all the way through. Everybody makes mistakes dating people they work with," he added.

But while dating co-stars hasn't always been successful for Hartnett, he did give a hint during that same Playboy interview that his relationship with Egerton was shaping up well.

"I’d have to get a car that’s safe for my kid," he said, when talking about the kinds of things he needs to earn money to pay for. "I don’t have a kid yet, but that’s the idea coming into my head these days," he revealed.

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