Chris Brown has released a freestyle version of Kanye West's "Way Too Cold," and his lyrics seem to have landed the controversial Grammy-winning hip-hop star in hot water with ex-girlfriend Rihanna.

On the track, Brown raps, "Don't f--- with my old bitch it's like a bad fur/ Every industry n---a done had her/ Shook the tree like a pumpkin just to smash her/ Bitch is breaking codes, but I'm the password."

Brown tweeted a link to the freestyle early Thursday morning (May 10) and was met with a prompt response from Rihanna, who tweeted, "Aw, poor dat #neaux1currrrr." She then immediately unfollowed Brown on the social network.

For his part, Brown hit Twitter again Thursday morning to issue a pseudo-denial that the song is about Rihanna. But in so doing, he appeared to take a shot at her, writing, "Assumptions! I didn't say any names so if u took offense to it then it's something you feel guilty about."

Interestingly, Brown's alleged verbal takedown of Rihanna comes just a few months after the stars reunited on a pair of much-debated duets, a move that many saw as a public statement that Rihanna had forgiven Brown for assaulting her the night before the 2009 Grammy Awards. Brown pleaded guilty to felony assault and accepted a plea deal of community labor, five years' formal probation and domestic violence counseling.

Rihanna appears on Brown's remix of "Turn Up the Music," and Brown cameos on a particularly explicit extended version of Rihanna's Talk That Talk track "Birthday Cake," which currently sits at #2 on the Billboard R&B/Hip-hop song chart.

"We did two records — one for my fans, one for his fans — and that way our fans can come together," Rihanna explained to Ryan Seacrest of her controversial decision to team up with her ex. "There shouldn't be a divide, you know? It's music and it's innocent.