That is exactly the kind of pressure Les Miserables star Eddie Redmayne faced when he took on the role of mega-famous astronomer, physicist and cosmologist Stephen Hawking in the biopic The Theory Of Everything.
"I was beyond intimidated," Redmayne told ET's Brooke Anderson on the red carpet at the sixth annual Academy of Motion Pictures Arts and Sciences' Governors Awards, held at the Dolby Theater in Los Angeles. "I didn't sleep for the best part of a year. But it was an extraordinary mixture of great privilege, but also deep fear."
So what did the real Stephen Hawking think of Redmayne's portrayal of his life?
"When Stephen Hawking, and his first wife Jane [Wilde], saw the film… and enjoyed it for us, that was a great reward," Redmayne shared. "He's been very generous. He's said some very lovely things."
The Theory Of Everything follows the life of the celebrated scientist from his early, heathy years studying science at Cambridge, his burgeoning relationship with Jane Wilde, being diagnosed with ALS, his meteoric success in the science world and his fight to overcome his debilitating disease.
Hawking was 21 when doctors first diagnosed him with Amyotrophic Lateral Sclerosis, and was given two years to live. Hawking is still alive, and is 72 years old.