Former power couple Chris Brown and Rihanna are making beautiful music again -- literally. Three years after the 22-year-old R & B singer beat the living crap out of then-girlfriend Rihanna, the musicians are back together again... at least on two new singles. Brown appears on a remix of Rihanna's song "Birthday Cake," while Rihanna puts in a guest appearance on a version of Brown's new song "Turn Up the Music." Rumors have been swirling that the amicable exes collaborated on two tracks, and now it's been confirmed as the songs hit the airwaves. Monday night, the 24-year-old Barbados beauty made it official Tweeting, "@chrisbrown Turn up the music remix #RihannaNavy #Teambreezy enjoy!!!" with a link to the song. What is most concerning about Rihanna's new birthday cake is the graphic lyrics, in which Brown sings, "Girl I wanna f-ck you right now. Been a long time I been missing your body. Lemme, lemme turn the lights down. When I, when I go down it's a private party." Talk about a piece of "Cake" that makes you want to gag. Ironically, Monday also happened to be Rihanna's bday, and Brown took the opportunity to remind everyone that he's back in her life to stay, Tweeting, "@chrisbrown: HAPPY BIRTHDAY ROBYN!" Last week, the ex-con attended her private birthday party and had fellow revelers sign non-disclosure agreements about his attendance. Supposedly, Brown and Rihanna's reconciliation is more professional than personal because he's dating a model. But with lyrics like that, it seems pretty transparent.