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Entertainment Tonight -- A rep for Leona Lewis denies allegations that the "Bleeding Love" singer somehow caused tension between Rihanna and Chris Brown at a pre-Grammy party.

Leona's record-label rep says that the singer was at the party "with her family and boyfriend and had nothing whatsoever to do with any argument that may have ensued between Chris and Rihanna. Any allegations that the pair had flirted are completely false."

A source tells ET that Rihanna introduced Chris to Leona at the party, and that Chris and Leona exchanged pleasantries for a couple of minutes.

Rihanna's rumored boyfriend is under investigation for alleged domestic violence. While some reports claim the woman involved was Rihanna, police have yet to identify the accuser. Meanwhile, Rihanna has reportedly canceled a second concert.