Instead, the normally affectionate twosome were embroiled in a domestic violence drama that left Brown, 19, booked on felony criminal threats charges and posting $50,000 bail after turning himself in to the LAPD on Sunday at 6:34 p.m. PST.
Sources say that Rihanna (real name: Robin Fenty), 20, was the victim in the alleged assault which occurred around 12:30 a.m. on Sunday. Responding to a 911 call about a disturbance, the LAPD took statements from a female with visible injuries, who named Brown as her attacker.
Just hours after the incident, witnesses spotted Brown and Rihanna leaving the London Hotel together around 7:30 a.m. on Sunday.
Later that evening, during the Grammy telecast for which both Brown and Rihanna were no-shows, bodyguards for the couple were seen moving their luggage out of the London.
The ramifications of Brown's arrest? Already charged with making criminal threats – defined in part as a situation where the victim "is in fear for [his/her] life" – the R&B singer may face additional charges at the discretion of L.A.'s district attorney's office.
To help him face the legal storm, Brown has hired attorney Mark Geragos, best known for defending convicted murderer Scott Peterson, Winona Ryder after a 2001 shoplifting arrest and Michael Jackson during his child molestation trial.
An R&B Romance Turned Sour?Rumored to be a couple towards the end of 2007, the singers were first photographed at the Grammys on Feb. 10, 2008. Often coy about their yearlong relationship, the two consistently refused to talk about their romance during interviews.
But the pair offered up other signs of their closeness, from matching star tattoos on their necks to holding hands and kissing at concerts.
Even at the Clive Davis party at the Beverly Hills Hilton on Saturday night, Brown and Rihanna looked cozy and happy.
But over recent weeks, they seemed to have hit a bumpy patch in their relationship.
"They've been fighting a lot lately," a source told PEOPLE. "Lots of ups and downs. One second they're all lovey dovey and then they're fighting like crazy. They're both pretty stubborn."
With reporting by JENNIFER GARCIA, KEN LEE and TIFFANY MCGEE
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