Is Jessica Jealous?

OK, we hope this is so not true, but knowing the level of insecurity that lives in La-La Land, we're betting this lil' rumor has some glimmer of truth to it. According to Star, Jessica Simpson isn't exactly thrilled that her ex, Nick Lachey has been linked to Laguna Beach star, Kristin Cavallari. Nevermind that KC is back with her old BF, or that Nick has supposedly moved on to someone else, word is Jessica has been spitefully prank calling her ex's ex! "[Jessica] was furious [when she found out]," says a source for the mag. "She thought it was insulting and embarrassing to be lumped together with Kristin." So what does any "mature" woman do when her former man moves on to a new hottie? "Jessica got a hold of Kristin's phone number and got a real kick out of making crank calls to it," the source snitches. "She'll ring Kristin up and just say nothing or try to order pizza or Chinese food and talk in different accents! She's even gotten some of her friends in on it. The pranks are harmless, but I think Jessica likes knowing that she's irritating Kristin in some way." Way to be the bigger person, girl.