According to Los Angeles Police Department records exclusively obtained by RadarOnline.com, the call came from a neighbor close to the tumultuous couple's Hollywood home at 1:30 a.m. on Thursday, May 2.
"Neighbors in both physical and verbal argument," LAPD notes stated. "Heard yelling 'Ouch.'"
The 29-year-old Nashville actress' mom, Lesley Vogel, told RadarOnline.com she was "in shock" after learning of the fight.
"I knew he had an incident with his father and he has a tendency to do that physical violence. Never had I thought it would be against Hayden or I would have addressed it sooner. I have addressed many things," she said.
In October, cops were called when Hickerson got into a boozy brawl with his father in South Carolina while his famous girlfriend was present.
A source told RadarOnline.com the rehab-alum actress' family deeply disapproves of the hard-partying romance.