The Theory Of Everything, a film study of Stephen Hawking's universe, premieres in Toronto

TORONTO (Reuters) - Actor Eddie Redmayne spent seven months working with a choreographer to prepare for the biggest role of his career, ironically a man whose body is reduced by disease to miniscule movement in his hand and face.

That man, British astrophysicist Stephen Hawking, is one of the most recognisable figures in the world and landing the role in the film The Theory Of Everything gave Redmayne "a moment of euphoria followed by a moment of deep fear."

The 32-year-old Londoner says he went "old-school"in his preparation and spent months with the choreographer at clinics with patients of amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease.

He took photos of a young Hawking to an expert to study the stages of his decline over 25 years, including the loss of his voice.

"I spent six to seven months working with this dancer to embed it my body," Redmayne told Reuters over the weekend ahead of the film's premiere at the Toronto International Film Festival yesterday.

By the time shooting started, Redmayne's goal was to have the physical part down so well that he could concentrate just on the emotions.

It looks like he pulled it off, judging by Hawking's critique.

"He gave Eddie the enormous compliment of saying 'I thought it was me on screen,'" said director James Marsh. "That tells you a lot about Eddie's performance. It passed the biggest test."

Variety critic Justin Chang said "Redmayne's performance nails all the outward manifestations without unnecessary exaggeration," and predicted the Focus Features film would fare well critically and commercially when it opens in North America on Nov 7.

Hawking, now 72, gave his blessing to the film, even though it is based on the memoir of first wife Jane Hawking who married the young genius when he was given two years to live.

She cared for him and their three kids over two decades and supported him in his high-flying career, including the writing of his book A Brief History Of Time for non-scientists to understand the universe. It has sold over 10 million copies.

"It is an unconventional love story," said Redmayne. "It is about young love, passionate love, family love, love of his subject. But it is also about the flaws and cracks in relationships."

Jane is played by British actress Felicity Jones over the 25 years of the film, from when she meets the gangly and fun-loving student at Cambridge to when he leaves her for another woman.

"People did underestimate Jane and her sheer determination and life force," said Jones. "Even though she was young, she had a very strong sense of herself."

The break-up scene may be one of the film's most memorable as a brilliant man struggles to communicate the end with a computerised voice lacking in musicality and a wheelchair that can only get so close.

"Even though Stephen is breaking up with Jane, there is a moment when all he can do to comfort her is push his wheelchair to nudge the back of her legs," said Redmayne.

The actor went to see Hawking right before he went to the screening of the film.

"I said 'Stephen, I am very nervous, I hope you enjoy the film, let me know what you think'," Redmayne recounted. "He spent a while typing out 'I'll let you know what I think, good or otherwise.' I said 'Stephen, if it's otherwise, will you just say 'otherwise'?'"

"Fortunately, after the film, he gave us the right to use his (synthesized) voice. We hear his voice and it's an iconic voice."

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