Actor Bradley Cooper loves it when audiences snigger at his stage portrayal of John Merrick because the real life 'Elephant Man' was laughed at every day.

Cooper plays the deformed sideshow attraction in a theatre production of the famous story, charting how Merrick dealt with his severe abnormalities.

The Hangover star admits he was wary of taking up the role in The Elephant Man in case fans laughed at his twisted frame and drooping features, but he vowed to use their reaction to inform his portrayal.

Cooper tells The Sunday Times Culture magazine, "I did think about it, especially in the beginning. I thought, 'Well, if I'm standing there in this makeshift diaper in front of people, there is a chance that people are going to start laughing.' Then I thought, 'Well, if they start laughing, that's actually fuel, because how many times has Merrick been laughed at?' I used to tell myself that all the time. I thought, 'No matter what they do, even if they throw something at you, that is all perfect.'

"To be honest with you, my whole life I've never been somewhere where it was, like, 'Yeah, of course you could do that.' It's always been challenging."

The Elephant Man opens in London's Theatre Royal Haymarket on Tuesday (19May15). The show ended a run on Broadway in February (15).