"It's a strange thing to think about how it's set up because if you count down to anything, it creates tension. ... It's designed to make the heart race and there's a part of you thinking, I hope it's not me because I can't bear any more tension," he joked.
Firth's film also won Best Picture.
"This is about two middle-aged men that become friends. ... This is not a genre that has lines around the block," Geoffrey Rush, Firth's co-star, told Winfrey.
"We knew that there was a wonderful story to be told there and so we knuckled down and got on and made the film. Bit by bit, audiences became aware of it and started to give it standing ovations and going to see it two or three times."
Rush, who helped produce the film, was nominated for Best Supporting Actor for his performance as Lionel Logue, King George VI's speech therapist. The film sparked a strong friendship among Rush, Firth and director Tom Hooper. The three have joked about their budding "man love."
"I think it's going to be quite sad that we have no excuse to get together and you know congratulate ourselves," Firth told Winfrey.
Firth presented Rush with a present on Sunday night's red carpet.
"He [Firth] did the most beautiful thing last night," Rush said. "When I arrived on the red carpet, I ran over and gave him a big hug and he took a 1946 King George VI shilling out of his pocket and gave it to me as a gift."
Best Supporting Actress winner Melissa Leo, who won for her performance in "The Fighter," apologized for dropping the F-word during her acceptance speech.
"I grew up with it as a part of my vernacular," she said. "I accept it as that. I brought my son up that way, but I also told him not in front of grandma ... people are offended and I apologize to all of them."
Leo is the first winner to ever say the F-word while giving an acceptance speech.
Leo said that she didn't expect to hear her name called Sunday night, despite having won at the Golden Globes and the Screen Actors Guild Awards.
"Maybe it's a little trick from all those years of going to auditions. … I learned how to play a mind game with myself," she said.
While Sunday night's nominees might have been nervous, Oscar co-host Anne Hathaway called hosting the award's show a "blast."
"I kept waiting to become nervous … and the whole ride from beginning to end was just pure joy and I was so grateful to be a part of a team," she told Winfrey.
The actress, who throughout the night changed quickly into seven dresses and one tuxedo, said that she and stylist Rachel Zoe looked at hundreds of dresses.
Hathaway said she and Franco took five weeks to film the opening number because Franco, a graduate student at both Yale and NYU, could only film on weekends.
Franco took a red-eye back after the Oscars so that he could make it to class today, Hathaway told Winfrey.
"I thought my co-host James Franco did an amazing job. … I think they idiot-proofed the show so they made me look really good," she said.