When producers first balked at the thought of Justin Timberlake portraying the leading man in sexy comedy Bad Teacher, ex Cameron Diaz fought tooth and nail to convince them of the singer’s acting skills.

It was a sweet move considering their history, but sources tell OK! Magazine that Cam has a secret agenda, one that is sure to anger Justin’s longtime lover Jessica Biel.

Read 10 Things You Didn't Know About Cameron Diaz

“Cameron’s such a bad girl: she made them rewrite the love scenes so that they’re even juicier — and longer,” a source divulged. “She doesn’t want to stir up trouble. But you know, she’s been cheated on - Justin cheated on her. She may not hold to the letter of the law when it comes to Jessica.”

A second insider was quick to note that the actress “had forgotten what great chemistry she has with Justin.”

Uh-oh! Jessica, consider yourself warned. (OK! Magazine)

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