Chris Brown during a hearing    Photo: Reuters

A whole lot has happened since Chris Brown's alleged assault on then-girlfriend Rihanna back in 2009.

But the RnB bad boy has been facing the repercussions of that fateful night ever since.

He finally left prison on Sunday after serving 108 days of a 131-day sentence for probation violation, TMZ reports.

Shortly after his release, the controversial singer tweeted his joy with the words: "Thank you GOD."

He also hinted that he's putting his arrogant persona behind him and planning on concentrating on his career, with the tweets: "Back to the Music and the Fans," and "Humbled and Blessed."

The 24-year-old had been sentenced to 365 days in May after admitting violating his probation by getting into a fight in Washington D.C. last year, but Judge James R. Brandlin gave him credit for the 234 days he has already spent in rehab and jail.

The judge also ordered Chris to attend therapy sessions twice a week and undergo random drug testing three times a week.

In February court papers showed he'd been diagnosed with bipolar disorder, severe insomnia and Post Traumatic Stress Disorder, which led to anger issues.

The troubled star had been in custody since being kicked out of a court-ordered rehab facility in March for breaking three internal rules.

He was first placed on probation in 2009 after the shocking assault on the Diamonds singer.

But he's not yet in the clear as he still faces a misdemeanor assault charge in Washington D.C. after he and his bodyguard Christopher Hollosy were accused of hitting Parker Adam outside a hotel and breaking his nose.

The trial for the incident starts in the coming months and he could face a maximum of six months in jail and $1,000 fine if convicted.

Rumours were flying of a reunion between the pair when Rihanna visited Chris in rehab in January.

But Rihanna was later linked to rapper Drake, and Chris's long-suffering girlfriend Karreuche Tran has stood by him during his prison stay.