"Theory of Everything" star Eddie Redmayne on playing Stephen Hawking

This piece originally aired Nov. 14, 2014.

As the world-famous physicist Stephen Hawking celebrates his 73rd birthday Thursday, the man who portrays him on the silver screen is winning rave reviews. In the movie, "The Theory of Everything," Eddie Redmayne shows how Hawking went from being a healthy young man into a wheelchair because of the debilitating disease, ALS.

The 32-year-old Redmayne was honored at the 2014 Hollywood Film Awards with the breakout acting award.

"God, it feels lovely," Redmayne told "CBS This Morning" co-host Gayle King. "It feels very lovely, but, you know I was luck enough to, I enjoyed acting at school. And somehow, I've been able to keep doing that thing that I love doing as a child as a profession every day. You feel like you're waiting to be found out. Every day, you feel like you're, you're sort of bragging your way through life. But, the fact that I'm being honored means that people are enjoying your work and then you get to keep doing this thing? My God, what a privilege."

His latest privilege is a treat for the audience as well. In "The Theory of Everything," Redmayne transforms himself into the brilliant physicist Stephen Hawking and takes the viewer on Hawking's real-life journey of love and loss as he battles the debilitating disease, ALS.

The actor watched old videos to capture Hawking's movements.

"I had so much documentary information, videos on an iPad and of him and I'd spent so long in front of a mirror, trying to replicate his facial muscles and really trying to get a sense of who he was," Redmayne said. "So it was less lines and it was more just, it was more learning to act, because as Stephen's muscles stopped working on his face, he uses any muscles that are left, muscles we wouldn't normally use, all these sorts of muscles...for his expression."

King felt that one of the most powerful scenes in the movie was when Hawking is told his diagnosis, and given a life expectancy of two years.

"His capacity to decide that every day after that two year period was a gift for him and his, the way in which he has lived his life so fully, squeezed everything out of every minute is for me, a great inspiration to us now," Redmayne said.

This may be his most drastic transformation, but its not his first. While playing Marius in the big screen adaptation of "Les Miserables," famed director Tom Hooper paid him the highest of compliments when he praised his ability to "disappear" into his character.

Eddie Redmayne on "The Theory of Everything"

King read a quote to Redmayne someone once said about him, "'He has -- he had a unique presence, even completely untrained, the sort of magnetism that only great actors have. He had the most astonishing natural acting ability and you can't teach that.'"

"Who said that? Who do I have to pay?," Redmayne asked. King told him it was his agent.

"I am paying him. That's wonderful. I knew he was worth the commission," Redmayne replied.

Kidding aside, the actor revealed how he sees his acting ability as a "continuous journey."

"It's like you try and live your life fully and draw from all the experience you have and pocket everything, meet people, meet as many people-- and live as full a life as possible, so that you can try and sort of distill some of that into the everyday, but I think what I loved about the 'Theory of Everything' and what I love about acting is when you see extraordinary stories, but very human stories and ones that you can relate to and can inspire you," Redmayne said. "And so that's kind of, that's basically how I try and go about it, anyway."