When preparing to play Lionel, Geoffrey says he was fortunate to meet the real Lionel's grandson two months before filming started. "He said, 'Oh, look, I've got all of these amazing papers and letters and diagnostic charts and photographs,'" he says. "I read letters from patients that he'd worked with who were shell-shocked victims. And to read the letters that they had written to him—even as long after the First World War into the 1930s—I got a real sense of the decency of the man. When you read what someone's written into their own diaries, you get a sense of their inner life."
Geoffrey also credits co-star Colin Firth with part of his nomination. "Colin is the most diligent, hard-working and very playful and extremely funny actor," he says. "In those very [first] one-on-one scenes, I'm sitting two meters away from a guy who's delivering very nuanced, very detailed, very awe-inspiring work. So you hope somehow that rubs off on you."