Roseanne Barr's ex-husband Tom Arnold thinks ''something happened'' to the star to make her post her controversial racist tweet.

The 59-year-old actor and comedian was married to Roseanne from 1990 to 1994, and has said something must have changed in the disgraced star before she posted a racist tweet earlier this year - in which she likened former White House adviser Valerie Jarrett to an ape - because she ''wasn't racist'' when he was married to her.

He said: ''She wasn't racist when I was with her. Look at her Twitter feed, look at how she is. She couldn't say one good thing about Obama. Something happened. But she wasn't like that [before], though.''

Tom was previously a writer for Roseanne's eponymously titled sitcom - which was cancelled in the wake of the controversy - and has said he had no idea that her character was due to be killed off when ABC launches its spin-off show 'The Conners' next month.

When asked about the spin-off - which will feature all the main cast except Roseanne - during an appearance on 'Watch What Happens Live' on Tuesday (25.0918), Tom said: ''Wait, I hadn't heard. Is that true? Oh my god! I don't think they're going to ask me back, either way you look at it.

''I don't know what to think. I think this, Sara Gilbert is a jinx on every show she's on this year, let me tell you that. I'm kidding.

''I wish them all the best, oh boy, I don't know.''

Meanwhile, 65-year-old Roseanne recently claimed that her character will meet her end at the hands of an ''opioid overdose'', which she says is ''cruelly insulting'' to the fans of the original program.

She said: ''Oh ya, they killed her. They have her die of an opioid overdose.

''There's nothing I can do about it. It's done. It's over. [But it] so cruelly insults the people who loved that family in that show.''