Eddie Redmayne has already gotten loads of critical acclaim for his role as genius Stephen Hawking in the film The Theory of Everything.

Recently, at the Golden Globe Awards, Redmayne won the award for Best Performance by an Actor in a Motion Picture, Drama. In his acceptance speech, Redmayne thanked the usual array of characters. But he also mentioned something else.

“I would like to thank our producers, my wonderful director, James Marsh, who basically held my hand as I had panic attacks daily.”

The notion of his nervousness, even panic attacks, is a theme that Redmayne continued in his conversation with Jennifer Lawrence in Interview Magazine recently. He said that it was his fear that drove him in his role as Hawking.

“I’m just one gigantic ball of rancid fear and self-consciousness,” he told Lawrence. “I’m entirely fueled by fear, so the fact that I knew it could be a catastrophic disaster made me unable to sleep, and made me work quite hard.”

That kind of nervousness had another effect on the already-thin Redmayne.

“I lost, like, 15 pounds at the beginning of the film.”

But Redmayne and his crew put the weight loss to good use for his role as Hawking. Unlike other movies famous for seeing lots of weight loss during the evolution of a character, Redmayne did not shoot this film in sequence.

“With the disease, Stephen did lose a lot of weight,” he explains. “But we couldn’t shoot chronologically, so we were having to jump between different time periods within the same day. Our extraordinary makeup artist, Jan [Sewell], and costume designer, Steven [Noble], did clever things like making the collars tight and my makeup look healthy in the morning, and then, if in the afternoon I was playing him older, they would mess with proportions—the collars would become bigger or they would use slightly oversized wheelchairs. But it was a real work in progress.”

And that is how you turn a minus into a plus.