Police were called to Karrueche Tran's home after Chris Brown allegedly followed her home from a nightclub at 3.30am.
Neighbors called 911 after the rapper was heard banging and screaming on her door after the pair reunited at Playhouse Nightclub in LA, according to TMZ.
Earlier in the night, he grabbed the V.I.P. table right next to hers, onlookers said.
The model - who recently dumped Chris after it emerged he fathered a love child - was upset and left, only to be followed by the star to her SUV, where an explosive argument ensued.
The pair are seen leaving the Los Angeles nightclub, with Karrueche looking visibly upset as Chris followed close behind.
TMZ reports that after Karrueche had left the nightclub to avoid her cheating ex, he followed her, and even joined her in her SUV as she drove away.
However, the website reported that his ex did not want him in the vehicle, and quickly made a stop to drop off the R&B star and his friends.