Eddie Izzard has admitted he thinks the European Union is difficult and too bureaucratic but urged young people to vote to stay in and "make it work".
The comedian said he considers himself a British European who wants the younger generation to have the same opportunities he did when he travelled around Europe in his youth.
He went head-to-head with Tory MEP Daniel Hannan at Reading University Students' Union for a debate ahead of next month's referendum.
Izzard listed big names including Barack Obama and Hillary Clinton and organisations like the International Monetary Fund and the Confederation of British Industry who he said had warned Britain leaving the EU would be a bad idea.
Of the EU he said: "It is a good force for change. It's difficult, it's too bureaucratic, I totally agree with that. But no-one's ever tried to do this before, so we should be trying to do it."
He added: "I just think we should stay in and try and make it work. We have to work like crazy to make it work. It's not easy but I just don't think pulling out is the right idea."
Izzard, who came out as transgender in 1985, wore a white t-shirt emblazoned with pink letters reading Stand Up For Europe and a matching pink beret.
Throughout the event, which saw both participants take questions from the audience, Izzard said "humanity" should be the priority.
He said: "It (humanity) overrides everything surely. It's the thing you've got to put at the top in trying to get to a place, a world where everyone has the same chance."
Countering Izzard's argument about making Britain's membership of the EU work better for us, Mr Hannan pointed to the Prime Minister's visits across Europe in a bid to secure a renegotiation.
He said these had failed and added: "Just ask yourselves one question. Look at how intransigent the EU showed itself to be – how unable or how unwilling to reform and ask yourselves this – If this is how we were treated now, the second largest net contributor, before we had our referendum, how would we be treated if we voted to remain?
"Any idea that we could stay in and then try and reform it having thrown that part away – it would be laughed at in Brussels."
The prominent Eurosceptic, who urged those watching the debate to "fire me" described the EU as "obsolete", adding: "It is a hangover from an earlier age – a relic of the 1950s."
He said: "I would not be asking you to serve me with my P45 if I were not confident that the economy as a whole will do better outside the European Union."
Izzard is travelling around 31 cities in the UK to speak to young people and urge them to register by June 7 to vote in the referendum on June 23.