The singer was convicted of the crime in 2009 but the pair have been working on a reconciliation in recent months.
Comedy writer and TV producer Jenny Johnson took to Twitter last night, inciting vitriol from Brown after she re-tweeted his post about looking old for his age.
“I know! Being a worthless piece of s*** can really age a person,” she wrote.
The singer responded to her saying: "Take them teeth out when u s****** my d*** HOE," and posted other comments, too graphic and misogynistic to publish.
Jenny took the opportunity to correct his spelling and said that his mother must be proud.
Chris responded by calling her “worthless” and a “thirsty b****”. He later claimed he was joking. “Just ask Rihanna if she mad??????” he wrote.
His Twitter account, which has over 11 million followers, was temporarily shut down following the spat.
Jenny told the 23-year-old to get help. She signed off with a summary of her feelings on the exchange.
“I have zero respect for a person who seems unapologetic for the terrible crime he committed and shows no signs of changing,” she wrote.
The remarks came a day after Rihanna tweeted a photo of Chris shirtless appearing to sleep on a bed.
The pair were also spotted together at a nightclub in Berlin on Thursday.
Chris broke up with girlfriend Karrueche Tran last month.
Both Chris and Rihanna have denied they are romantically involved despite being seen together several times since the split.