R&B star Chris Brown has been questioned by police in Los Angeles over a complaint of assault.
The 19-year-old singer pulled out of his performance at the Grammy Awards, as did his pop star girlfriend Rihanna.
Police said Mr Brown argued with an unidentified woman on Saturday night while sitting in a car.
Mr Brown, who walked into a police station at 1900 local time on Sunday (0300 GMT on Monday), was later released on $50,000 (£34,000) bail.
He left the police station around an hour after the Grammy Awards had ended.
Los Angeles police did not identify the woman who had made the complaint against Mr Brown.
Shortly before the Grammys ceremony, organisers said: “We have just been informed that Rihanna will not be attending tonight’s 51st Annual Grammy Awards. We’re sorry she is unable to join us.”
Police said Mr Brown and the woman got into an argument while sitting in the parked car in the city’s Hancock Park neighbourhood.
“After stopping his car, Brown and the woman got out and the argument escalated,” a Los Angeles Police Department statement said.
“The woman suffered visible injuries and identified Brown as her attacker.”
Police received an emergency call reporting the disturbance but when officers arrived, Mr Brown had left the scene.
Rihanna was due to sing Live Your Life/Disturbia as the second performance of the night at the Staples Center, while Mr Brown was to sing Forever.
They were both nominated in the pop collaboration with vocals category, Brown for No Air with American Idol winner Jordin Sparks; and Rihanna for If I Never See Your Face Again with Maroon 5.
Mr Brown was also nominated for male R&B vocal performance for Take You Down.
The couple had attended a pre-Grammy Awards party together on Saturday evening.