Chris Brown has opened up about the night he assaulted his ex-girlfriend Rihanna, describing how their violent relationship ended up with him punching her.

Barbadian-born singer Rihanna was pictured in 2009 with bruises and a split lip after R&B singer Brown, 28, attacked her in his car in what apparently started out as an argument about another woman.

In the new documentary film Chris Brown: Welcome To My Life, the star said that Rihanna had been kicking and hitting him during the argument, and that he then lost his temper and “really hit her”, and bit her arm. Speaking about his feelings eight years on, Brown says he felt like a “monster” and that the altercation would “haunt him forever”.

Chris BrownChris Brown performing at the Hot 97 SummerJam in 2017

The two met in New York in 2004 as teenagers, but their relationship went sour after Brown admitted being unfaithful with an employee (having previously denied it). From there on, the couple fought increasingly until the fateful night in February 2009, having attended a pre-Grammy event.

“She didn't care, she just didn't trust me after that,” he said. “From there, it just went downhill because it would be fights, it would be verbal fights, physical fights as well… We were fighting each other. She would hit me, I would hit her. But it never was OK.”

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“I remember she was trying to kick me. It was just her just being upset. But then I really hit her. With a closed fist, like I punched her and it busted her lip. And when I saw it I was in shock. Why the hell did I hit her? From there, she just spit in my face, spit blood in my face, so it enraged me even more. It was a real fight in a car.”

In June that year, Brown pleaded guilty to one count of felony assault and accepted a plea deal of community labour, five years of probation, and domestic violence counselling. Anti-domestic violence campaign groups were up in arms at the sentence, saying that it wasn’t severe enough.

“I look back at that picture and I'm like, 'That's not me, bro'. I hate it to this day,” Brown finished. “That's going to haunt me forever.”

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