Police say singer Chris Brown is under investigation following a row over a parking space in Los Angeles.
Officers were called to a recording studio in West Hollywood on Sunday for a report of six men fighting.
In a statement, the Los Angeles County Sheriff's Department said: "The altercation allegedly led to Chris Brown punching the victim."
The Grammy-award winner, who's 23, is currently on probation for an attack on Rihanna in 2009.
He's due back in court on 6 February to update a judge on his progress.'Suspect'
Explaining the argument outside the recording studio, LA County Sheriff Department spokesman Steve Whitmore told Newsbeat that Chris Brown had been named as "a suspect in a battery report."
"Battery is a misdemeanour. It basically means unwanted touching," he said. "This could have been a minor scuffle, it could have been pushing. It's an ongoing investigation."
Online reports have named Frank Ocean as a person who was punched during the fight, although police won't confirm that.
Ocean tweeted a reference, writing "got jumped by chris and a couple [of] guys."
So far there has been no official comment from Chris Brown or Frank Ocean.