Chris Brown deletes Twitter account following feud with comedian

Chris Brown performs at the MTV Video Music Awards on Aug. 28, 2011, in Los Angeles.

R&B singer Chris Brown has deleted his Twitter account after a vulgar online exchange with comedian Jenny Johnson.

Johnson says she's now receiving death threats on Twitter from Brown's supporters.

The fight started when 23-year-old Brown posted a picture of himself, saying he looked old. Johnson replied: "I know! Being a worthless piece of (expletive) can really age a person."

Brown fired back with a series of crude sexual jokes. Johnson posted a link to a news story about Brown's 2009 assault on singer Rihanna.

Before deleting his account, Brown wrote: "Just ask Rihanna if she mad??????" The on-again-off-again couple has been seen together recently. Rihanna reportedly flew to Berlin last Thursday to spend time with Brown. Prior to taking off, she tweeted: "All alone in my big ole jet!!! See u soon lover." They also collaborated on a song for Rihanna's upcoming album.

A representative for Brown's record label didn't immediately respond Monday to an email seeking comment.

Brown had 11.6 million followers on Twitter.

This isn't the first time Brown has fled the site. In December 2009, he ditched his @mechanicaldummy account after writing a series of tweets targeted against the music business. He again scrapped his Twitter page in November 2011 following a rant about the continued focus on 2009's Rihanna attack.