Watch Rihanna Perform The Day Before Chris Brown Arrest

Pop star sang three songs at Timbaland's pre-Grammy party, with Brown in the crowd.

Just one night before an alleged physical altercation with boyfriend Chris Brown, [artist id="1940303"]Rihanna[/artist] was onstage performing at [artist id="503162"]Timbaland[/artist]'s pre-Grammy party. Tim and Rihanna were celebrating the release of a "Rehab" remix, along with guests [artist id="1244412"]Keyshia Cole[/artist], [artist id="1269"]Jay-Z[/artist], [artist id="1225081"]T.I.[/artist], [artist id="1873941"]Omarion[/artist] and [artist id="1961441"]Brown[/artist].

"Bum bum be-dum, bum bum be-dum bum," Rihanna's background singers sang to kick off Rihanna's performance of "Disturbia."

Brown looked on from his VIP section and later made his way to the dance floor, where he stood with his friend Omarion.

"Los Angeles, I know y'all know how to party," Rihanna told the crowd. "Let me know you're ready to party with me."

Her plea led to "Don't Stop the Music"; the audience clapped along to the unstoppable beat. "Umbrella" was her closer. She started off acoustic, then the band kicked in for the radio version.

Rihanna's next performance was scheduled to be at the Grammys on Sunday, but she and Brown both had to bow out of the show.

The news of trouble between the couple has sent their fans, friends and family members reeling.

"All I will say is, it's so devastating," Kanye West told Ryan Seacrest during his Tuesday morning radio show. "I feel like, just as a person, I don't care how famous she is, or even if she worked at McDonald's, that should have never happened. It should have never come to that place."