His comments in The Defiant Ones stand in stark contrast to previous remarks about the incident. He was notoriously unapologetic in a 1991 interview with Rolling Stone, telling the magazine: "I just did it, you know. Ain't nothing you can do now by talking about it. Besides, it ain't no big thing - I just threw her through a door."
Barnes' assault - and allegations that Dre assaulted other women including his former girlfriend, Michel'le - resurfaced in 2015 after the release of the biopic Straight Outta Compton.
Barnes penned a piece for Gawker, titled: "Here's What's Missing From 'Straight Outta Compton': Me and the Other Women Dr. Dre Beat Up."
"When I was sitting there in the theatre, and the movie's timeline skipped by my attack without a glance, I was like, 'Uhhh, what happened?,' " Barnes wrote. "Like many of the women that knew and worked with N.W.A, I found myself a casualty of Straight Outta Compton's revisionist history."
Dre responded with what many considered a lackluster apology. "I apologize to the women I've hurt," he said in a statement to the New York Times. "I deeply regret what I did and know that it has forever impacted all of our lives."
Barnes is featured in The Defiant Ones, where she recalls interviewing N.W.A on her hip-hop show Pump It Up in 1990, following Ice Cube's departure from the group.
"From the very moment it started, the energy was bad," said Barnes, who had been friends with Dre and the members of N.W.A. Things reached a tipping point after Barnes' producer insisted she film a rebuttal from Ice Cube, which aired during the N.W.A segment.
Barnes recalls running into a drunk Dr Dre at a Def Jam party a few months later in January 1991. "The next thing I know, he snatched me up," Barnes said. "And when I say he snatched me up, my feet were off the ground. It was like, 'shit.' You know, like the strength and the rage. And, you know. Everybody knows the story from there."
Director Allen Hughes intersperses Barnes and Dre's interviews with news reports about the assault, and the civil suit Barnes filed shortly after.
"I don't think I was out of touch with reality, but I was Dr Dre, and this was a very low point in my life," a solemn Dre says.
He continues: "I've done a lot of stupid s*** in my life, a lot of things that I wish I could go and take back. I've experienced abuse. I've watched my mother get abused, you know? So it's like, there's absolutely no excuse for it. No woman should ever be treated that way. Any man that puts his hands on a female is a f***ing idiot. He's out of his f***ing mind. And I was out of my f***ing mind at the time. I f***ed up. I paid for it. I'm sorry for it. And I apologised for it.
"I have this dark cloud that follows me, and it's going to be attached to me forever. It's a major blemish on who I am as a man, and every time it comes up, it just makes me feel f***ed up. So it's just like, what do I do? What do I do to get rid of this dark cloud? I don't know what else to do. I'm learning. I'm trying to become a better person, become a better man.
"In the end, I've hurt people that I care about. And for that, I'm really sorry."
Hughes spoke about Dre's apology during a June appearance on "Sway in the Morning," Sway Calloway's SiriusXM show. "What happened with Dee Barnes, Dre's dealing with it directly," Hughes said when Sway asked if the documentary would touch on the assault. "And guess what, Dee Barnes is in the film as well," Hugh added to audible gasps from others in the studio.
When Sway asked if Dre apologized in the series, Hughes said "absolutely" and that neither he nor Dre would have done the documentary without including an apology.
Hughes also referenced Barnes' 2015 Gawker piece, telling Sway that he had already filmed Dre's apology for The Defiant Ones at the time.
"We had already had the apology in the can for a year, and it was so surreal because I was like damn ... what are you going to tell people that Dre already dealt with this, opened up about it? We had to sit on it for another two years."
As for Barnes, she seems to have forgiven Dre for the incident. "From a personal standpoint, I feel like I've handled it well," she says in The Defiant Ones.
"I had to stand up just because I would probably never forgive myself if I hadn't."
"I went through the anger and the dismay and, you know, I worked those things out to where I got to a place of peace," Barnes adds.
"Forgiveness, it's not really about the other person. Forgiveness is ... for you. You do it for yourself because what are you going to do with all that anger?"
* Sky TV says The Defiant Ones is not currently available to broadcast outside the US.
