Jennifer Aniston can't stand to be away from 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 to 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!"

Friends say the actress has fallen hard for her new beau, despite the age difference and his notorious reputation as a ladies' man