R'n'B star Chris Brown has pleaded guilty to beating his former girlfriend pop star Rihanna.

At the Los Angeles Superior Court yesterday, Brown admitted to one count of felony assault relating to an incident that occurred hours before the pair were due to perform at the Grammy Awards.

Under the terms of a plea bargain agreed with prosecutors, Brown will be given five years probation and six months community service. He will be formally sentenced on August 5.

The 20-year-old singer was arrested on February 8, hours after a party in Los Angeles.

According to an affidavit filed by an LA police detective, the altercation took place in a car when Rihanna checked Brown's mobile phone and found a text message from another woman.

Detective De Shon Andrews wrote that Brown attempted to push Rihanna out of the vehicle before punching her repeatedly. He also bit her ear, the affidavit states.

He then allegedly threatened to kill her when she pretended to phone her assistant to get police help.

According to the detective, the alleged assault left Rihanna with a mouthful of blood. Brown is also alleged to have tried to choke Rihanna.

Following the incident, pictures apparently showing the female singer's beaten and swollen face were leaked onto the internet. In court in LA yesterday, Rihanna had been on standby to give evidence.

Instead, after the guilty plea was entered, the singer heard details of a "stay away" order imposed by judge Patricia Schnegg.

Under the ruling, the former couple must stay at least 50 yards from each other, except at music industry events where the distance is reduced to 10 yards.

After Brown entered his guilty plea, Judge Schnegg said "I think it is commendable you took responsibility for your conduct."