Since “The Theory of Everything” debuted at the Toronto International Film Festival in September, Eddie Redmayne has been at the forefront of the ever-growing Best Actor race. Not that the 32-year-old star, who portrays Stephen Hawking in the new film, has awards on the brain.

“The stakes felt so high from day one on this, because ultimately Stephen and Jane [Hawking, his ex-wife] are going to watch this film. The fact that they liked it, they were the ultimate critics,” Redmayne told HuffPost Entertainment in September. “That for me meant the world. Anything else that comes with that is wonderful. But that Stephen and Jane loved it is the greatest thing.”

But if Redmayne is nominated, he needn’t worry about finding an Oscar clip. “The Theory of Everything” is loaded with emotional moments, including one harrowing sequence that kept Redmayne awake at night during production.

Toward the end of the film, Hawking comes to America for a speech. As he’s taking audience questions, a woman near the front row drops her pen. Director James Marsh then imagines a moment where Hawking — who was diagnosed with motor neurone disease, or ALS, in 1963 — slowly begins to rise out of his wheelchair. He walks off the stage, bends down and proceeds to hand the woman her wayward writing instrument, a simple gesture that is commonplace for so many viewers. But in a single cut, Hawking is back in his wheelchair, the dream of full body movement snapped back to his reality.

“I was so scared of it. In the script it read so beautifully,” Redmayne told HuffPost Entertainment about the scene. “I had spent these months working on the physicality, but I was so scared to try that.”

Redmayne actually spent six months preparing to play Hawking. He watched videos of the theoretical physicist, interviewed Hawking’s family for pointers and enlisted a full team of support: Marsh, makeup artist Jan Sewell, costume designer Steven Noble and dancer Alex Reynolds, who worked on the zombie movements in “World War Z.” But the dream sequence only locked into place once Redmayne realized that he could reverse his own process to its beginning.

“In the end, it became so simple. It was sitting there going, ‘What was the first thing that went? The first thing that went was maybe the hand, so let’s make that the first thing that moves. Then the feet.'”

The finished product is the film’s high point. “I find it weirdly moving,” Redmayne said. He wasn’t the only one. “That was the thing that Lucy and Tim Hawking [Stephen’s children with Jane] said to me the other day when they saw the film,” Redmayne said, he voice rising with emotion. “It was extraordinary for them to see what their dad could have looked like in his 40s.”

“The Theory of Everything” is out now.