Chris Brown was spotted partying in a LA nightclub on Tuesday just hours after he was sentenced for assaulting former girlfriend Rihanna.

The singer was joined by friends and security personal at the LA Lounge, where he reportedly danced to songs including Dirty Diana by Michael Jackson.

"He didn't seem to care at all that everyone was watching him," a source told People.

"He was in a totally good mood, just hanging out with his buddies. Then all of a sudden he decided to put on a little show. Everyone went wild."

Rihanna in New York yesterday.

Earlier in the day, Brown, who pleaded guilty to assault, was sentenced to five years' probation for attacking Rihanna in February.

The R&B singer was also sentenced to 180 days community labour and ordered to attend domestic violence counselling.

Meanwhile, Rihanna was pictured looking in good spirits as she dined with a friend in New York yesterday.

Chris Brown in the dock