We're told the guy suddenly grabbed the woman by the throat and would not release her. Justin and his friend started screaming at the guy to let her go, but he only screamed back "Go f*** yourself". maintaining his grip.
The alleged altercation took place at a party hosted by Patrick Schwarzenneger on the night of April 14.
TMZ reports that Bieber arrived at the shin-dig with a mate before the came to the woman's rescue. Party sources indicate the man may have been on drugs, and they woman in question may have been his ex-girlfriend.
The guy was thrown out of the party at that point, and later - while chasing a auto that he believed Justin was riding in - the man was arrested by the cops. The source goes on to reveal that the police showed up and arrested the man. He yelled the singer's name as he started hitting the auto.
Bieber acquitted himself well on the dance floor, particularly when compared to celebrities-caught-dancing-in-the-wild Coachella incidents of the past.
The Grammy-winning singer has been in town attending the Coachella Music Festival alongside a horde of fellow A-listers.
The festival has had an impressive line-up this year featuring Beyoncé, Eminem, The Weekend and of course Yodel Boy who has been one of the unexpected big hits of the annual gathering. The power of the Internet, eh?