Jessica Simpson is reportedly “really jealous” of her ex-boyfriend, John Mayer’s new relationship with Cameron Diaz.

A source close to the Dukes of Hazzard star told Us Weekly: “She had her mouth open a mile wide when she found out. She just freaked.”

John and Jessica dated for seven months before finally separating in May but the source added: “she thinks about him all the time .. She is so not over him.”