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Rihanna and Chris Brown are back together in more ways than one.

On Rihanna's 24th birthday Monday, the singer released a full-length version of her song "Birthday Cake" (from the album Talk That Talk) featuring new verses by her abusive ex Brown, 23.

"Girl I wanna f-ck you right now. Been a long time I been missing your body," Brown sings on the remix. "Lemme, lemme turn the lights down. When I, when I go down it's a private party."

Brown also tweeted a link to the new version of his song "Turn Up the Music," which featured additional music by Rihanna; the "We Found Love" singer later retweeted it.

Brown assaulted then-girlfriend Rihanna just before the Grammy Awards in 2009. He later pleaded guilty to felony charge and was sentenced to five years probation.

Although Brown is currently dating aspiring model Karrueche Tran, multiple sources confirm to Us Weekly that he and Rihanna have been secretly hooking up over the past year.

"Rihanna loves to live dangerously," says a Rihanna pal. "Talking to and hooking up with Chris is all part of that."