Chris Brown opens up about his 2009 assault on Rihanna in his new documentary, Welcome to My Life. In the film, the R&B singer details his relationship with his then-girlfriend Rihanna and how everything went so wrong.

Brown, confessed to punching RiRi when they were arguing in a Lamborghini after attending a Clive Davis Grammy party. “I felt like a f---ing monster,” he said as he details of how the assault went down.

Prior to the altercation, the couple were at the Clive Davis Grammy party when another woman, whom Brown had relations with prior to dating Rihanna, approached their table. Rihanna was initially upset but quickly got over it. “She started drinking a little bit, we both was drinking a little bit.” Afterward, that’s when things took a turn for the worse.

Brown said that while they were in the Lamborghini he told Rihanna to look at his phone to deny that he was still seeing the woman in question and the singer saw a text message from her.

“She starts going off, she throws the phone,” he recalls. “'I hate you.' Starts hitting me. We’re in a little Lamborghini. She’s fighting me. I’m like, 'Look, I’m telling you the truth, I swear'... She hits me a couple of more times and it doesn’t go from translation to, ‘Let’s sit down, I’m telling you the truth.’ It goes to, ‘Now, I’m going to be mean, be evil.' I remember she tried to kick me, but then I really hit her, with a closed fist, I punched her. I busted her lip. When I saw it, I was in shock. I was like, 'F---, why the hell did I hit her?'”

“From there she just spit in my face,” the singer continued. “Spit blood in my face and it enraged me even more.” After he pulled over, Rihanna allegedly faked throwing the car keys out the window and called out for help.

“I get out of the car and I’m looking for the keys and somebody yelled and she yells out her door, ‘Help, he’s trying to kill me," he said.

Soon after their fight, a police photo emerged of Rihanna’s bloody and bruised face.

“I look back at that picture and I’m like ‘That’s not me, bro, that’s not me,’” he said. “I hate it to this day. That’s going to haunt me forever.”

Watch Chris Brown's candid video above.