Chris Brown performs at the BET Awards at the Microsoft Theater on Sunday, June 25, 2017, in Los Angeles. Picture: AP

Chris Brown was in a state of "shock" after he'd assaulted Rihanna.

The controversial musician has opened up about the night he became violent towards his ex-girlfriend in February 2009 for a new documentary, 'Chris Brown: Welcome To My Life', revealing their relationship took a violent turn after he admitted to his sexual past with a woman who once worked for him, having previously denied he'd been involved with her.

READ: Chris Brown gives unsolicited opinion about Rihanna's new man

Recalling the incident at the pre-Grammys Clive Davis party in 2009, Chris said: "I remember she tried to kick me, just like her beating s**t, 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, I was like, f**k why did I hit her like that?

"From there she's spitting blood in my face, it raised me even more. It's a real fight in the car and we were driving in the street ... She tried to grab for my phone, and I'm not giving her my phone, to throw it out the window."

The singer admitted the incident changed their relationship forever, saying Rihanna lost all trust in him from that moment.

Chris shared: "She hated me. After that, I tried everything. She didn't care, she just didn't trust me after that. 

"From there, it just went downhill because it would be fights, it would be verbal fights, physical fights as well. Mutual sides, it is the first time I get to say anything."

Chris, 28, still has strong feelings for Rihanna, but he admitted their relationship was unhealthy for the both of them.

He confessed: "I still love Rihanna, but I'm just going to be honest - we would fight each other, she would hit me, I would hit her, but it never was OK. 

"It was always a point to where we talk about it like, 'What the f**k are we doing?'"

The 'Loyal' hitmaker also admitted the night he assaulted his ex-girlfriend proved to be a turning point in his life.

He explained: "If I go on stage, I got a scratch on my face, and I've got to explain it, like 'Oh I fell', or if you got a scar or a bruise, you got to put make-up on. 

"S**t, I'm not ever trying to put my hands on any female."