"I wasn't working a lot in Austria, so I had time to make friends and go through all the bars," he says. "At one point, I came back to work about three weeks later having gone on sort of long binges with my friends, and [director] Robert Wise said 'You know we're going to have to redo your costume because you're fatter than Orson Wells."
After seeing the final product and Julie's performance, Christopher says he changed his mind about the film. "I think [it was] almost the most natural performance she's given in her career," he says. "Her whole face was just radiant with reality and sureness and unself-consciousness, and she gave such an extraordinary, immortal performance. I couldn't help but turn around and start respecting the movie, which was beautifully made, of course."
In the years since filming The Sound of Music, Christopher has appeared in more than 100 films, including The Insider, The Inside Man, Up and, most recently, The Last Station, which earned him an Oscar® nomination for his portrayal of the great Russian writer Leo Tolstoy. A few years ago, he also published his memoir, In Spite of Myself.
At 80 years old, Christopher's acting career is still going strong. "[I'm getting] more work now than I've had all my life," he says. He's currently balancing work on both the stage and screen, though he says his heart belongs to theater.
"There's no excitement that can top the sound of laughter and the real-life reaction of an audience," he says. "There's nothing like it."