Rihanna ain’t creepin’ with Timberlake — and she’s wants Jessica Biel to know just that!

The pop star had her assistant track down Jessica’s cell number and frantically phoned JB, after whispers that Justin, 28, has been romancing the Caribbean-born beauty gained momentum late last month, a close pal of Rihanna’s blabs in the Oct. 12 issue of The National Enquirer. Rihanna told the former 7th Heaven actress that despite the gossip, JT is not bringing “SexyBack” with her!

Jessica’s 2 1/2 year romance with Justin is reportedly hanging by a thread, due in part to the former boy bander’s inability to commit.

“Rihanna doesn’t want to be pegged a homewrecker,” the Rihanna camp insider says. “She loves Justin, but only as a friend.”

While the two are collaborating with one another on Rihanna’s upcoming fourth album, the singer insists the relationship is strictly platonic.

“Rihanna apologized over the ridiculous nonsense that’s been printed. Rihanna has been cheated on in the past, and one thing she would never do is take another woman’s guy. Sure, she and Justin are close, he’s producing her CD.”

Jessica was on the Vancouver of her latest film, The A-Team, when she received Rihanna’s call. The girls chatted pleasantly and even agreed to get together for lunch, according to The Enquirer.