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    Josh Hartnett on His Famous Ex-Girlfriends: I Don't Recommend Dating Your Costars!

    Josh Hartnett Jamie McCarthy/Getty Images

    Josh Hartnett is opening up about his famous ex-girlfriends.

    In a new interview with Elle, the 35-year-old actor says he doesn't exactly suggest people follow in his footsteps when it comes to dating costars (we're talking about you, Scarlett Johansson!).

    "I don't recommend it to young actors," Hartnett tells the mag. "You can make a lot of enemies in the business that way. But when you work with somebody every day, it's like trial dating. You develop a fantasy about them. It doesn't always work out, does it?"

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    Scarlett Johansson, Josh Hartnett Jeff Vespa/WireImage for LIONSGATE

    Hartnett, who has somewhat of a history of dating beautiful actresses, said he never bragged to his friends about romancing gorgeous Hollywood gals.

    "They want to hear all about what you're doing," he said. "But they don't want to hear any complaints. Back when I dated a few very beautiful, very famous girls, I said something once—it wasn't really a complaint—and my buddy said, ‘Oh my God, my diamond shoes are too tight.' He coined the phrase."

    When asked what the secret to keeping a girlfriend happy is, Harnett dished, "Let them be on set whenever they want, with whichever costar you're working with. Never say the scene is too sensitive. They get very suspicious."

    Sure sounds like he's learned some valuable dating lessons!

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