Authorities are investigating allegations that Grammy-winning singer Chris Brown assaulted a man - named in reports as rival musician Frank Ocean - in a West Hollywood car park.
The Los Angeles County Sheriff's Department said deputies responded to a report on Sunday night of six men fighting.
It said the altercation, reportedly over a parking space, "allegedly led to Chris Brown punching the victim".
The 'victim' was not identified but the celebrity website TMZ, which first reported the clash, said the fight also involved Frank Ocean, a nominee in the upcoming Grammy Awards.
Ocean later tweeted that he "got jumped by chris (sic) and a couple guys".
He also wrote on Twitter: "cut my finger now I can't play w two hands at the grammys."
Brown's attack on singer Rihanna on the eve of the 2009 Grammy awards overshadowed the show.
He was also injured last year in a brawl with hip-hop star Drake's entourage at a New York nightclub.
And it is not the first time that Brown's and Ocean's paths have crossed.
Last year 23-year-old Brown was forced to deny aiming a homophobic slur towards Ocean when asked his opinion on the star.
He denied making the comments on his Twitter page, posting: "My opinion on the whole Frank Ocean subject is ...Love who u wanna love. It’s ur decision."
Ocean came out in a post on his blog last year.