Rihanna and Ryan Phillippe: Hot new couple?

Feb 23, 2011 at 2:30 p.m. ET

Rihanna and Ryan Phillippe are having a steamy fling and are trying really hard to keep it on the DL!

RihannaRyan Phillippe just ended his short-lived romance with Amanda Seyfried, but the Hollywood playboy has already jumped into bed with another woman: Rihanna!

A source says that Rihanna and Phillippe are totally getting it on, and the fact that they all but ignore each other at public events is just a cover for their torrid affair.

"She thinks he's hot," a source told Us Weekly. "They totally had sex. And it wasn't even the first time!"

"They initially hooked up when things were strained with [Rihanna's ex] Matt Kemp back in early December."

People who attended the Two Kings charity event on February 19 say the pair played it cool. "There was no PDA," said an insider. "They hung out a bit, but were discreet. It is still very casual."

As far as Phillippe's relationship with Amanda Seyfried, it is totally over. "They are not dating anymore. And it's not a big deal for either of them," said a pal. "At one point, there was a chance it would develop into something more serious, but it never did."

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