"The King's Speech" continued its winning momentum going into the 83rd annual Academy Awards, taking home the big prize of best picture, while its star Colin Firth received the Oscar for best actor; "Black Swan" star Natalie Portman received the award for best actress.
Tom Hooper, the director of "The King's Speech," pulled off a surprising win over "The Social Network" director David Fincher. "Speech," which led the number of nominations with 12, received a total of four Oscars, including best original screenplay.
"The Fighter" co-stars Melissa Leo and Christian Bale were among the early winners, receiving Oscars for best supporting actress and best supporting actor.
In a self-deprecating and emotional speech, Firth joked, "I have a feeling my career has just peaked." With his typical British reserve, he said he was "experiencing stirrings" that were "threatening to turn into dance moves."
Firth thanked his wife, Livia, for the award and "everything good in my life," while the pregnant Portman thanked "my love," her fiancee and "Black Swan" choreographer Benjamin Millipied for giving "me my most important role of my life."
Leo got the night off to a raucous beginning, when she dropped the F-bomb during her speech.
When Bale accepted his award, he told the audience, "I'm not going to drop the F-bomb, like she did. I've done that plenty before."
Both were expected to win after taking home the same award at the Golden Globes. But some doubt had been cast on Leo, after the ads she took out in the Hollywood trades promoting herself backfired.
The race was opened up to competitors Hailee Steinfeld ("True Grit"), Helena Bonham Carter ("The King's Speech"), her fighter co-star Amy Adams and Jacki Weaver ("Animal Kingdom").
Still, Leo pulled off the win in the end.
Kirk Douglas, who walked on stage with a cane, dragged out the announcement of the Leo's name. On stage, Leo bowed to Douglas and asked him to pinch her as the two flirted.
"I'm shaking in my boots here," Leo said, taking a deep breath. As she waved to the audience sitting in the rafters, she dropped the F-bomb, prompting co-host Anne Hathaway to exclaim later, "It's the young and hip Oscars."
Recovering, Leo thanked the Academy.
"This has been an extraordinary journey," she said about the award season. "It's about selling motion pictures and respecting the work."
A humbled Bale took the stage saying, "What the hell am I doing here?" Among those he thanked was Dicky Ecklund, the washed-up fighter he played in "The Fighter."
President Barack Obama made a surprise appearance at the Oscars. During an introduction for best song, he cited "As Time Goes By" from "Casablanca" as his favorite movie theme song.
Later in the telecast, Randy Newman, who has been nominated 20 times and won once previously, received the Oscar for "We Belong Together" from "Toy Story 3."
Tom Hanks gave out the first awards of the night for cinematography and art direction.
Tim Burton's "Alice in Wonderland" took home the first Oscar for art direction.
Cinematographer Wally Pfister won his first Oscar for "Inception," and gave credit to Christopher Nolan, who was snubbed for a best director nomination. "Inception" took home several technical awards, for sound mixing, sound editing and visual effects.
Pfister beat out perpetual nominee Roger Deakins, the cinematographer on "True Grit." Deakins has yet to win an Oscar.
Hanks pointed out the newly redesigned red and gold envelope that holds the winners' names. To honor the 70th anniversary of the Academy Awards, designer Marc Friedland gave the Oscar envelope a makeover from the ordinary white envelope and plain announcement cards.
"Toy Story 3," which is also nominated for best picture, won best animated feature, as expected.
The two films started out even in the Oscar tally, following the screenplay awards.
Aaron Sorkin received the Oscar for best adapted screenplay for "The Social Network" and joked that his daughter's guinea pig will have to give him some respect now.
Backstage, Sorkin mused about Facebook founder Mark Zuckerberg.
"Mark, I think he's been an awfully good sport about all this," he said. "I don't think anyone here would want a movie made about the things that they did when they were 19-years-old."
David Seidler won the Oscar for best original screenplay.
"My father always said to me I would be a late bloomer," the gray-haired writer said, receiving applause. "I believe I'm the oldest person to win this particular award. I hope that record is broken quickly and often."
In a twist, he thanked his children for having faith in him and told stutterers around the world, "We have a voice, we have been heard."
Later, backstage, Seidler said, "I've been flooded with the most wonderful e-mails and text messages from my fellow sutterers. Because, I'm still a stutterer ... to have these people tell me their personal stories really moves me to tears."
Trent Reznor, the former frontman of Nine Inch Nails, and Atticus Ross won the Oscar for best original score for "The Social Network," which also took the trophy for editing.
"The Wolfman" won the Oscar for makeup, while Colleen Atwood took home her third Oscar for "Alice in Wonderland."
Oprah Winfrey announced the winner for best documentary feature, "Inside Job."
"Not a single financial executive has gone to jail and that's a shame," the film's director Charles Ferguson said to applause.
Denmark's "In a Better World," took home the prize for best foreign language film.
"The Social Network" was an early favorite in the Oscar race, after winning big at the Golden Globes and topping critics' best lists at the end of last year.
But in the final weeks before the Oscars, it's been all about "The King's Speech," which won the top prizes at the Producers, Directors and Screen Actors Guild Awards.
The other big contest of the night, best actress, featured one of the night's most anticipated match-ups, between youngster Natalie Portman, who won a Golden Globe and a SAG award for "Black Swan," and veteran actress and four-time nominee Annette Bening, who scored a Golden Globe and a slew of critics circle awards for "The Kids Are Alright."
Bening, a four-time Oscar nominee, didn't go home completely empty-handed. She was accompanied by husband Warren Beatty, who had already declared her the best actress in the world.