Brown, who will next month be sentenced to 180 days of community service for the February 8 incident, posted the apology on his official website in a two-minute statement made directly to camera.
"I wish I had the chance to live those few moments again, but unfortunately I can't," Brown said. "I'm not going to sit here and make any excuses. What I did was inexcusable.
" The 20-year-old singer said he had apologised repeatedly to Barbados-born "Umbrella" singer Rihanna and revealed that he continued to seek help to prevent a repeat of his outburst.
"I have told Rihanna countless times, and I'm telling you today, that I am truly, truly sorry that I wasn't able to handle the situation differently and better," he said.
"As many of you know, I grew up in a home where there was domestic violence, and I saw first-hand what uncontrolled rage could do.
"I have sought and I am continuing to seek help to ensure that what occurred in February can never happen again ... What I did was unacceptable, 100 per cent. I can only ask and pray that you forgive me, please.
" Brown escaped a jail sentence after a plea deal with prosecutors over the assault, which took place as the couple drove home from a pre-Grammy Awards party.
The incident shocked the music world and left Rihanna nursing cuts and bruises to her face, forcing her to cancel a scheduled performance at the Grammys in Los Angeles.
Affidavits filed in the case alleged Brown slammed Rihanna's head against the window of a car the couple were travelling in before repeatedly punching and biting her.

