An eyewitness tells Life & Style that Chris Brown, 19, and girlfriend Rihanna, 20, had a big blowup at pre-Grammy party on Friday night, about 24 hours before Chris allegedly assaulted the singer early Sunday.

"I saw Chris Brown and Rihanna fighting at the Verizon party [at Boulevard 3 nightclub in Hollywood] on Friday night," the eyewitness tells Life & Style. "They were in this room and they were just screaming at each other, totally cussing each other out.

"They were screaming 'F*** you,' 'No, f*** you' at each other, back and forth. They were right in each other's face.

"It was scary. They were surrounded by all these execs and they were all just ignoring it, as if it was something they saw every day.

"It was so shocking. It's just so awful."

For more on Chris and Rihanna, check out the new issue of Life & Style, on newsstands Wednesday!

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