Rihanna: Chris Brown 'Blacked Out' During Assault

Rihanna Chris Brown Assault Good Morning America 20/20

Rihanna admits she briefly reunited with Chris Brown after he attacked her in February -- but never felt the same way about him again.

"I just said to him, 'I can't do this.' I resented him. I resented him so much," the singer, 21, tells Diane Sawyer in part two of the interview that airs Friday night on "20/20."

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"And I always put the tough face on and try to, I can do anything face, and just try to play it off. But he knew. He knew it. He kept asking me, 'You hate me, don't you?'" she continues.

"And I would lie and I would say, 'No, no. And... I did hate him... Everything about him annoyed me," admits Rihanna of Brown, 20. "So finally... I just said, we can't... we can't do this. I cannot continue to do this."

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Rihanna also opens up for the first time about the actual fight, which sent her to the hospital with bruises, and resulted in Brown later pleading guilty to assault.

"It wasn't the same person that says I love you. It was not those... eyes," she says. "He had... no soul in his eyes. Just blank...He was clearly blacked out. There was no person when I looked at him."

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Rihanna goes on, "All I kept thinking all the time: When is it going to stop? When it is going to stop?"