That Smarts! Jennifer Lopez Left Casper Smart Over ‘Extreme Jealousy' Towards Co-Star, Source Claims: The ‘Chemistry Was Undeniable’

It’s been nearly three months since Jennifer Lopez left her ex-boyfriend Casper Smart, and a source on the set of Lopez’s latest film, The Boy Next Door, tells RadarOnline.com that her steamy chemistry with her sexy co-star ended the relationship!

“Casper would get very jealous and possessive of Jennifer while they were filming this movie because Ryan and her got extremely close,” the source says, referring to Ryan Guzman, 26, who plays Lopez’s obsessed lover in the upcoming thriller.

“It led to so many fights that the crew did not want him being on-set,” the source adds.

“Casper would come and watch Jennifer film love scenes with Ryan and it drove him crazy,” the source tells Radar. “And for good reason… the chemistry between Jennifer and Ryan on and off screen is undeniable!”

Although it is uncertain as to whether or not anything went down with the American Idol judge and her sexy younger co-star, sources close to Guzman tell Radar, “Ryan thinks that she is one of the sexiest women alive.”

When Lopez, 45, was asked in June about her breakup with Smart, 27, during SiriusXM’s Morning Mash Up, she said, “I’m good right now. We just got out of a relationship. There needs to be time for reflection and alone time. That’s where I’m at right now.”

Did Jennifer Lopez make the right move by leaving Casper Smart? Sound off in the comments below!