Chris Brown and his girlfriend Rihanna pulled out of their performances at the Grammy Awards, after Chris was questioned by police.
Officers in Los Angeles said the R&B singer had argued with a woman, who hasn't been named, and there had been a complaint against him.
The 19-year-old singer went to a police station on Sunday night.
He was later released on bail, which means officers have let him go home while they carry out investigations.
Chris was questioned over an argument he's thought to have had with a woman, while they were sitting together in a parked car.
Rihanna pulled out of her performance
They said the woman had been hurt, and had accused the singer of attacking her.
Both Chris and Rihanna had been nominated for Grammy Awards.
Rihanna was due to sing Live Your Life/Disturbia at the ceremony, and Chris was to sing Forever.
The couple had been to a pre-Awards party together on Saturday evening.