Eddie Redmayne has revealed portraying Stephen Hawking in The Theory Of Everything was "demanding".
The Les Miserables star admitted he had some nerves about playing the award-winning physicist in James Marsh's biopic, which also stars Felicity Jones as Hawking's first wife Jane.
"There's a moment of excitement when you get a part like this, which soon gives way to dread," he told Esquire in the January issue. "We knew if we scr**ed it up we'd be lambasted because Stephen is such an icon."
Eddie said the pressure to get the story right was of utmost importance.
"I want this story to be seen. The stakes were so high," he said. "One of the first things my mate Charlie Cox said to me was, 'The great thing about this part is that you have no option but to give it everything'. He was right."
The 32-year-old actor, who is engaged to Hannah Bagshawe, worked with a dance choreographer to understand the deteriorating effects ALS had on the scientist.
"I'm not going to lie, it was demanding and pretty intense. But we had fun, too, just as Stephen does. He doesn't live a disease, he lives a forward-thinking, funny life," he said.
And he admitted he got star-struck when he met Hawking.
"It's amazing, the aura he has. You're so used to how he looks, the silhouette and the voice, and I was really nervous. I just waffled, talking about him, to him. It was pretty embarrassing," he said.
Eddie also revealed how Felicity brought out Hawking's "flirtatious" side. He joked: "Felicity came in, they got on like a house on fire. Stephen was incredibly flirtatious. A complete player."