Hollywood star Ewan McGregor pulled out of an appearance on Good Morning Britain - saying he objected to host Piers Morgan's comments about the women's marches.
The Star Wars actor, 45, was due to appear on the ITV breakfast show to talk about his new movie, the Trainspotting sequel.
But after arriving at the studio, and discovering that Morgan was presenting the show, he made his feelings clear when he tweeted his fans: "Was going on Good Morning Britain, didn't realise Piers Morgan was host.
"Won't go on with him after his comments about women's march."
Morgan, 51, who co-hosts Good Morning Britain with Susanna Reid, 46, hit back on-air as well as on Twitter, writing on social media: "A real man would have come on and debated it with me, not run away like a coward."
And he added of the Trainspotting star: "Vainspotting."
He tweeted: "You should be big enough to allow people different political opinions. You're just an actor after all."
Morgan told viewers of the ITV show: "Sorry that's unprofessional. But you turn up. We are allowed to have different opinions in the world.
"Do we all just have to agree? Am I not allowed to express any dissent? What has (it) come to when actors are telling the world how they should think?"
He added: "Get over yourself."
Reid added more diplomatically: "Such a shame. Challenge views where there's difference. Would have liked to see that debate on air - it's an important one."
Morgan had previously voiced his displeasure at the protests which took place around the world.
The TV host had objected to the marches in a series of tweets, saying: "I'm planning a men's march to protest at the creeping global emasculation of my gender by rabid feminists. Who's with me?"
He added: "I'm very supportive of women's rights. I just don't like the rather sexist label Women's March.
"Let's be honest, ladies ... today's Women's March is just an anti-democratic protest at Trump winning the presidency."
And he added: "Just need Kim Kardashian and Emily Ratajkowski to post bird-flipping topless selfies to support Women's March for the farce to be complete."
Hundreds of thousands of people joined women's marches in London and Washington DC as protests were held around the world following President Donald Trump's inauguration.
At least 500,000 people gathered for a rally outside the US Capitol building in Washington, while organisers said an estimated 100,000 descended on central London on Saturday as similar events were staged in Edinburgh, Bristol and cities across the US.
Celebrities showing their support included Madonna, Katy Perry, Drew Barrymore, America Ferrera and Michael Moore.