Hollywood stars have reacted furiously to the decision to pull a film about the assassination of the North Korean leader - with Ben Stiller branding it "a threat to freedom of expression".

The Interview has been shelved after hackers threatened to launch terrorist attacks on cinemas that showed the film.

The comedy, which stars Seth Rogen and James Franco, was due to be released in America on Christmas Day and come to the UK in February.

But hackers calling themselves Guardians of Peace threatened to launch attacks like the September 11 atrocities.

Sony Pictures said it was pulling the movie "in light of the decision by the majority of our exhibitors not to show the film".

But some of America's biggest stars accused film bosses of bowing to bully-boy tactics.

Ben Stiller said: "Really hard to believe this is the response to a threat to freedom of expression here in America."

Stressing that he was speaking "as a creative person, not any kind of expert", he added: "Terror threats shouldn't dictate free expression. That's my opinion."

Rob Lowe, who stared in the West Wing, said: "Wow. Everyone caved. The hackers won. An utter and complete victory for them. Wow."

He compared the decision to pull the film to the former British prime minister Neville Chamberlain's policy of appeasement with Adolf Hitler.

He tweeted: "Saw @Sethrogen at JFK. Both of us have never seen or heard of anything like this. Hollywood has done Neville Chamberlain proud today."

Film-maker Michael Moore joked: "Dear Sony Hackers: now that u run Hollywood, I'd also like less romantic comedies, fewer Michael Bay movies and no more Transformers."

Comedian Jimmy Kimmel branded the move an "un-American act of cowardice that validates terrorist actions and sets a terrifying precedent".

In a statement Sony Pictures said: "The studio, which has been shaken by hacker leaks over the past several weeks, said it respected and shared in the exhibitors' concerns.

"We are deeply saddened at this brazen effort to suppress the distribution of a movie, and in the process do damage to our company, our employees, and the American public.

"We stand by our film-makers and their right to free expression and are extremely disappointed by this outcome."

US investigators have said North Korea was behind the cyber attacks on Sony Pictures.

The hackers have leaked a string of embarrassing emails which have rocked the film studio.

The attack was possibly the costliest yet for a US company, said Avivah Litan, a cyber-security analyst at research firm Gartner. "This attack went to the heart and core of Sony's business - and succeeded," she said.

"We haven't seen any attack like this in the annals of US breach history."

Efraim Levy, a financial analyst who covers parent company Sony Corporation for research firm S&P Capital IQ, said: "Artistic freedom is at risk. Are we not going to put out movies that offend some constituencies?"

In an interview with ABC News, US president Barack Obama said of the hacking: "The cyber attack is very serious.

"We're investigating and we're taking it seriously. We'll be vigilant. If we see something that we think is serious and credible then we'll alert the public. But for now, my recommendation would be that people go to the movies."

The film might have been shelved but it has only served to ratchet up interest in the comedy, with The Interview merchandise already attracting bids of hundreds of pounds on eBay.

Posters and fridge magnets are being offered for sale on the internet auction site, with collectors keen to own a piece of memorabilia for a film which may never be seen.