US television network ABC has dramatically cancelled the revival of hit sitcom Roseanne after star Roseanne Barr posted an “abhorrent” racist insult on Twitter.

Barr sparked outrage overnight by comparing black former Obama administration official Valerie Jarrett to an ape.

“Roseanne’s Twitter statement is abhorrent, repugnant and inconsistent with our values, and we have decided to cancel her show,” ABC Entertainment president Channing Dungey said in a statement on Wednesday morning (AEST).

Bob Iger, chief executive of ABC’s parent company Disney, added on Twitter: “There was only one thing to do here, and that was the right thing.”

In the since deleted tweet, Barr compared Ms Jarrett, 61, to an ape. She wrote that if the Islamist political movement “muslim brotherhood & planet of the apes had a baby = vj.”

Ms Jarrett has declined to comment on Barr’s tweet. Photo Getty

Barr, 65, later apologised “for making a bad joke” about Ms Jarrett, who was born in Iran to American parents.

Australia’s Network Ten followed ABC’s lead later Wednesday, pulling Roseanne from both its channels, Ten and Eleven, saying it was “appalled and disgusted” by Barr’s tweet.

Roseanne was ABC’s biggest hit of the 2017-2018 season. The show drew an average of 18.7 million viewers, second only to CBS sitcom The Big Bang Theory, according to Nielsen data through May 20.

Ms Jarrett, via spokesman Jordan Finkelstein, declined to comment.

Before the cancelation, black comedian Wanda Sykes, a consulting producer for Roseanne, tweeted that she was leaving the show.

Sarah Gilbert, who plays Darlene on the show, wrote on Twitter that the cancellation was “incredibly sad and difficult”.

This is incredibly sad and difficult for all of us, as we’ve created a show that we believe in, are proud of, and that audiences love— one that is separate and apart from the opinions and words of one cast member.

— sara gilbert (@THEsaragilbert) May 29, 2018

In the fallout, Barr’s agents, ICM Partners, dropped Barr as a client.

“We are all greatly distressed by the disgraceful and unacceptable tweet from Roseanne Barr this morning,” ICM Partners said in a statement on Wednesday.

“What she wrote is antithetical to our core values, both as individuals and as an agency. Consequently, we have notified her that we will not represent her. Effective immediately, Roseanne Barr is no longer a client.”

Barr signed with ICM last August, just as the reboot of Roseanne went into production.

The original Roseanne aired from 1988 to 1997. It featured a blue-collar family, the Conners, with overweight parents struggling to get by and was praised for its realistic portrayal of working-class life.

President Donald Trump latched on to the rebooted show’s huge viewership as evidence that his supporters, which include Barr, want shows that speak to their concerns.

-with AAP