Even In Rehab, Chris Brown Knuckles Up Over Frank Ocean Dispute.

R&B singer Chris Brown may be receiving treatment for his anger issues in a rehabilitation center, however, new reports claim he is countersuing over last winter's altercation with fellow crooner Frank Ocean.

According to reports, Brown's reasoning behind the countersuit is based on Ocean's cousin asking for millions in damages.

You'll recall ... Chris and Frank got into it outside a recording studio back in January. The building was damaged and Sha'Keir Duarte -- Frank's cousin -- claimed he was kicked and beaten by one of Brown's bodyguards. Duarte sued Chris in August for his injuries. Now Chris has fired back, claiming Duarte provoked the fight by threatening to kill him. In the countersuit -- obtained by TMZ -- Chris claims Duarte kicked and punched him. And get this ... Chris -- who is currently in rehab for anger management and faces criminal assault charges in D.C. -- claims he attempted to avoid the confrontation "with the aggressive and hostile Mr. Duarte." Chris says this is a shakedown for $$$, saying Duarte's demand for $2 million is absurd. (TMZ)

Buzz behind one of Ocean's pals pressing charges against Brown heated up the 'net over the summer.

A man who claims he was punched and kicked by a member of Chris Brown's entourage during a fight at a recording studio sued the R&B singer on Tuesday for assault and battery. Sha'keir Duarte sued Brown for unspecified damages in Los Angeles Superior Court, claiming he suffered a concussion as well as humiliation and mental anguish as a result of the attack. Brown's attorney Mark Geragos called the case frivolous and said it amounted to an attempted shakedown. (Associated Press)

Back in March, Brown made sure to diffuse speculated issues between him and Ocean following the incident.

"With the Frank Ocean situation, I'll put it like this, it's in the past. Some stuff went down, but it's whatever. It's always sensationalized and always blown out of proportion. I got respect for his music. I got respect for everybody else, so I ain't really trying to really go back down that route. Everything for me is moving forward. I do my music now so I'm good." (Power 106)

Despite the physical confrontation, Ocean issued an open statement in February and said he would not press criminal charges.

AS A CHILD I THOUGHT IF SOMEONE JUMPED ME IT WOULD RESULT IN ME MURDERING OR MUTILATING A MAN. BUT AS A MAN I AM NOT A KILLER. I'M AN ARTIST AND A MODERN PERSON. I'LL CHOOSE SANITY. NO CRIMINAL CHARGES. NO CIVIL LAWSUIT. FORGIVENESS, ALBEIT DIFFICULT, IS WISDOM. PEACE, ALBEIT TRITE, IS WHAT I WANT IN MY SHORT LIFE. PEACE." (Frank Ocean's Tumblr)