Talk about "Blonde Ambition"! Dazzling divorcee Jessica Simpson has taken her dating game to the next level by starting a hot new romance with co-star Luke Wilson - while continuing her fling with John Mayer.

"Jessica certainly got back in the swing of things - and she owes it all to Luke," a close pal told The ENQUIRER.

"A year after her divorce, she's rediscovered just how much fun dating can be, and Luke is more than happy to play along."

Luke, 35, first met Jessica, 26, on the set of "Blonde Ambition" - and the two immediately hit it off. The comedy - an updated version of the Melanie Griffith hit "Working Girl" - is filming in Shreveport, La. It didn't take long for the on-set friendship to blossom into a surprise romance.

"The last thing Jessica was looking for was a new romance," revealed the pal. She and John Mayer, 29, have been talking by phone constantly while she's on location.

"But Luke is one of the most charming guys in Hollywood - not to mention handsome," said the pal. "He was very generous with Jessica, constantly helping her run through lines and rehearse to make their scenes magic."

Get all the details in this week's ENQUIRER!