When will people learn … DO NOT MESS WITH SHARON OSBOURNE! The famous rock manager and Osbourne matriarch was embroiled in an argument at a Grammy week event with fellow music manager Jordan Feldstein that led to Osbourne throwing a plate of food at Feldstein.

Feldstein, who repped Sara Bareilles, was later fired by the pop star after the incident. According to reports, Feldstein and Osbourne clashed at a Clive Davis pre-Grammy party at the Beverly Hilton. He was first spotted arguing with Osbourne's daughter Kelly in the ballroom before she stormed off and Sharon intervened.

A witness told The Hollywood Reporter that "Sharon walked up to him pointing her finger and screaming." As things became more intense, Osbourne threw the plate of food at Feldstein's lap and poured water over his head. Bareilles was reportedly seated nearby as the incident occurred. The photo above was taken not long after the incident with Feldstein walking away (in the white shirt) and Osbourne still clearly upset.

Feldstein, who is the older brother of actor Jonah Hill, is rumored to have made comments about Osbourne's son Jack and his wife that started the confrontation.