Roseanne Barr ''crossed a line that cannot be crossed'' with her racist tweet, according to ABC president Channing Dungey.

The 65-year-old actress had her eponymously titled sitcom cancelled by the television network after she made racist comments on Twitter toward Valerie Jarrett, a senior adviser to former President Barack Obama.

But the company have now claimed they had dealt with ''multiple instances'' of inappropriate behaviour involving Rosanne, and felt her comments were the ''last straw'' which they had to take action over.

ABC president Channing Dungey told Deadline: ''[The decision] was actually made very swiftly, and what I'm going to have to say is that it was nice that it was so clear to everyone that there wasn't a lot of debate and discussion about it. We knew what we wanted to do, and we did it. For us, we have had multiple instances with Roseanne, and certainly this tweet crossed the line that cannot be crossed, but it was for us a sense of enough is enough and something had to be done.''

Channing claimed she had had ''multiple conversations'' with her staff and with Rosanne about her behaviour, but claimed that despite her history, the Twitter scandal would have resulted in ''some action''.

In a separate interview with The Hollywood Reporter, Channing added: ''It's not a secret that she has had a tendency in the past to be sort of outspoken and go off-book. We've had multiple conversations about wanting to keep the focus on the show and not to let some of the other stuff eclipse the show. So, in some ways, this was a last straw. But it was also such an egregious tweet that it felt like no matter what, there would have been some action that we would have taken.''

ABC are set to launch a spin-off of 'Rosanne' entitled 'The Conners' - which will star the cast of 'Roseanne' minus the titular star - in October, and Roseanne recently claimed the network would be ''lucky'' if the show is successful without her.

She said: ''I'd tell more jokes about myself than I do anybody else, because to me, comedy is very personal, and that's what makes it funny. That's what made people like the 'Roseanne' show - because they saw themselves in [me], or have an aunt, or their mom or their sister, somebody in their family was, you know, a loud, outspoken woman who loved her family.

''That was what I brought to television and what kicked everybody's a** in the ratings. [ABC] should be so lucky that they'll ever get anywhere near that. And they can't take that away from me, no matter what's happened.''