Jennifer Lopez & Jason Statham: Sparks on Set!

On-set affairs between costars are a common occurrence — and now Star has learned that Jennifer Lopez and British stud Jason Statham, the male lead in her upcoming crime thriller Parker, have heated up off screen as well. The problem? He's in a long-term relationship with gorgeous Transformers: Dark of the Moon babe Rosie Huntington-Whiteley, 24, who was 4,500 miles away, attending London's Fashion Week, while Jason and Jennifer were getting cozy in Florida. Star has the inside scoop in this week's issue!

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An eyewitness at Cielo, the eatery at the Boca Raton Resort & Club, tells Star that on Sept. 21, "Jennifer and Jason had dinner, just the two of them. It's a really romantic restaurant on the top floor of the hotel overlooking the water, and it's very exclusive. They were really engaged in their conversation and definitely enjoyed being together."

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And the 42-year-old mom of twins, who's in the midst of a divorce from singer Marc Anthony, was also apparently getting close to Jason, 39, behind closed doors. "They were at the hotel for about a week filming scenes and spent a lot of time in a room on the 26th floor, another source tells Star in this week's issue. "They had room service delivered on several occasions. One time, she ordered fruit, bread, a burger...and champagne."