Chris Brown -- Brutalizing Rihanna Is My 'Deepest Regret'

Chris Brown is calling the infamous Rihanna beating in 2009 the "deepest regret of my life, the biggest mistake."

Brown told the UK Mirror, "Sometimes you row, you fight, with the one you love and things get said, stuff spirals."

He added, "But she loves me -- what can I say? I’m forgiven ... but, yes, I worked hard for it.”

You'll recall, Brown infamously brutalized Rihanna on the night of the Grammys back in 2009. He pled "guilty" to felony assault following the incident and was sentenced to probation and community service. He and Rihanna are now officially back together.