Comedian Stephen Fry has said he is "prepared to go to prison" over the "Twitter joke" trial.
Fry was at a benefit gig for a man who is appealing against his conviction for sending a menacing communication.
Paul Chambers had tweeted: "Crap! Robin Hood Airport is closed. You've got a week... otherwise I'm blowing the airport sky high!"
Fry argued that Chambers' tweet was an example of Britain's tradition of self-deprecating humour and banter.
Chambers' case has become a cause celebre on Twitter, with hundreds of people reposting his original comments in protest at the conviction.
"This [verdict] must not be allowed to stand in law," Fry said, adding that he would continue to repeat Chambers' message and face prison "if that's what it takes".
Among the other celebrities lending their support to the fundraising evening were Al Murray, Rufus Hound, Katy Brand and Father Ted writer Graham Linehan.
Speaking generally about the internet and freedom of speech, Linehan told the audience: "We've got this incredible tool and we should fight any attempt to take it out of our hands."
The benefit gig, at London's Bloomsbury Theatre, aimed to raise funds for Chambers' appeal.
Freedom of speech
The aim of the organisers is that he will not be forced to drop his case because of the possibility he would have to pay the prosecution's legal costs were he to lose.
Few of the stars were prepared to assign wisdom to Chambers' original tweet, however.
Sitting inconspicuously in the stalls, Chambers was subjected to plenty of good-natured ribbing from those on stage and was variously described as a knucklehead, a nerd and a "doughnut".
Murray even branded the gig the "Save Paul Chambers from his own stupid destiny event".
But everyone seemed united by a desire to protect freedom of speech or at least the ability to recognise the difference between jokes and menacing terrorist threats.
Chambers' lawyer, David Allen Green, also addressed the audience, briefing them on the key details of his case.
Although he was careful not to criticise the courts, he said the decision to find his client guilty "does not make me proud to be an officer of the court".
"We should be able to have banter," he concluded. "We should be able to speak freely without the threat of legal coercion."
Chambers - who now lives in Northern Ireland but lived in Balby, Doncaster, at the time - sent the message to his 600 followers in the early hours of 6 January 2010. He claimed it was in a moment of frustration after Robin Hood Airport in South Yorkshire was closed by snow.
He was found guilty in May 2010 and fined £385 and told to pay £600 costs.
His appeal is likely to go before the High Court later this year.