IMAGE ID # 1880907 Grammy day was supposed to be a glittery affair for R&B’s reigning “It” couple, Chris Brown and Rihanna. But things went horribly amiss. About the time Brown was scheduled to be singing “Forever” onstage at Los Angeles’ Staples Center, he was instead detained by police, being questioned for allegedly roughing up Rihanna. Brown, 19, turned himself in at the Wilshire station around 6:30 p.m. and was booked on suspicion of felony domestic battery. Bail was set at $50,000 and he remains in custody. Rihanna, 20, suffered visible bruises on her face during an altercation that took place hours earlier. Both in turn balked on scheduled Grammy performances. A spokeswoman for Brown’s label declined comment. Rihanna’s publicist, Amanda Silverman, said 20-year-old “Disturbia” singer was involved in an unspecified traffic mishap. “Rihanna is well,” the rep said. “Thank you for concern and support.” The incident occurred about 12:30 a.m. in the Hancock Park area, apparently as the two were heading home from Clive Davis’ annual pre-Grammy bash, where they had been all smiles. In a statement, police say Brown and his companion “became involved in an argument. After stopping his car, Brown and the woman got out and the argument escalated. The woman suffered visible injuries and identified Brown as her attacker.”

Pictured: Rihanna and boyfriend Chris Brown dance the night away at ‘Palais Maillot’ in Paris, France.

CR: ANG/ Fame Pictures

12/19/2008 — Chris Brown, Rihanna — (C) 2009 Fame Pictures, Inc. – Santa Monica, CA, U.S.A – 310-395-0500 / Sales: 310-395-0500