Authorities in Los Angeles are investigating the teenage singer and dancer on a domestic violence allegation. Brown has been dating Rihanna who, like Brown, was to perform on last night's live telecast.
The couple was seen together Saturday night at a pre-Grammy event. And authorities say the incident took place early Sunday morning.
Authorities didn't release the name of the alleged victim in the assault, but say the woman suffered evident injuries.
A text statement from Rihanna's publicist says: "Rihanna is well," but doesn't elaborate.
What the El!?! Editorial:
Radaronline.com reports Rihanna's car was spotted at Cedars-Sinai Hospital in Los Angeles and that the star had been seen at the hospital.
TMZ.com reports Rihanna, who's real name is Robyn Fenty, was the alleged victim and a law enforcement source says she suffered "contusions and bite marks."
Bite marks! That's just crazy.
Brown turned himself in to authorities even as the show was being aired live from Los Angeles and was briefly held before posting $50,000 bail.
Officially, he is being investigated on suspicion of making a criminal threat, a felony. It's up to the district attorney's office to decide what, if any, charges Brown will face.
The absence of both Brown Rihanna had producers scrambling to fill the two slots in which the stars were supposed to be performing. The singers were to sing separately on the show, and producers had to work quickly to fill the gaps.
One fill-in ensemble featured Justin Timberlake, Boyz II Men, Al Green and Keith Urban.
The Rock was supposed to introduce Rihanna and ended up hacking his way through an awkward intro for the newly formed foursome.
Brown was supposed to perform "Forever" as the fifth performer on the show. That performance was scratched.
Instead of introducing Brown, LL Cool J joined Jay Mohr in introducing Sugarland and Adele.
Grammy chief Neil Portnow said later he learned three hours before the show that Rihanna wouldn't be there.
He declined to comment on Brown's situation but did say: "Musicians are like everyone else; they have their trials and tribulations."
And now Wrigley says it's suspending ad campaigns featuring Chris Brown as its spokesman for Doublemint gum.
The company stopped short of saying they will drop the troubled R&B star completely.
A company statement expresses concern about what it calls "serious allegations made against Chris Brown."
Wrigely said it would suspend any current advertising or any related marketing until the situation is resolved, adding that the 19-year-old should be "afforded the same due process as any citizen."