Jen's 1,000-Mile Booty Call

Looks like Jennifer Aniston just can't stand to be away from new boy toy John Mayer!

Last week, only days after the new couple's romantic poolside romp, the former Mrs. Brad Pitt found herself over 1,000 miles away from her man as he returned to NYC and she remained in Miami t0 continue shooting Marley & Me. And sources on the set say it was obvious the 39-year-old actress had her musician man on her mind.

"Every spare moment Jen had on the set, she was on her cell phone with John," the insider tells OK!. "Between takes, she'd whip out her phone and start chatting away. I didn't know it was possible for someone to spend so much time on the phone!"

Whatever Jen told John during their constant conversations, it was enough to get the 30-year-old hunk back on a plane to Miami, where sources say that last weekend he covertly snuck into Dolphin Stadium, where his lady-love was shooting a scene for the film.

"They got down and dirty in a make-out session, right inside the stadium!" the insider reveals to OK!.

Friends say the actress has fallen hard for her new beau, despite the age difference and his notorious reputation as a ladies' man (he's had previous flings with Jessica Simpson, Jennifer Love Hewitt and Cameron Diaz).

"She's usually pretty cautious when it comes to dating," a close friend of the star tells OK!. "But with John, she's decided to wing it and follow her gut."

For the entire scoop on Jen and John's new romance, pick up the new issue of OK! — on sale everywhere!