The superstar Canadian singer was at a Coachella party on Saturday night when he punched a guy in the face and threw him against the wall after the man in question grabbed an unnamed woman by the throat at the party.
The man reportedly approached the woman, grabbed her by the throat and refused to let go despite demands from Bieber and a pal.
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TMZ reports that Bieber arrived at the shin-dig with a mate before the came to the woman's rescue. Security then escorted the man out of the party.
According to TMZ, the news site also reported that the man, who was believed to be under the influence, chased an SUV believing that Justin was inside.
Police reportedly arrested the man, who was apparently on drugs and angry at his alleged victim, who was his ex.
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Bieber acquitted himself well on the dance floor, particularly when compared to celebrities-caught-dancing-in-the-wild Coachella incidents of the past.
Bieber has been enjoying his time at Coachella since Friday.
The little fella probably doesn't know what's hit him, there he was one minute happily yodelling away in his local supermarket the next he's performing on Ellen and putting in an appearance at the same event as some of the biggest artists in the world.
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