The air at the Kodak Theatre was thick with royal atmosphere as "The King's Speech" claimed four trophies on the Oscar night, taking home best picture, actor, director and screenplay as the top winner at the event.

Natalie Portman was named best actress for her role as a tortured ballet dancer in the psychological thriller "Black Swan," while Melissa Leo and Christian Bale took home supporting acting prizes for their work in "The Fighter."

"The King's Speech," a vivid account about King George VI of England struggling to overcome a hereditory stammer, came out on top of the 10-film field of best-picture nominees, topping critics' favorite "The Social Network."

Tom Hooper, won the best-director Oscar for helming the period piece. This was his first nomination -- and he gave the credit to his mother.

"My mom in 2007 was invited by some Australian friends ... to a fringe theater play reading of an unproduced, unrehearsed play called `The King's Speech,"' he said onstage. "Now she's never been invited to a play reading before."

The top acting prizes all went as expected, with each of the winners already having added Golden Globes and Screen Actors Guild Awards to their mantles.

Firth, 50, won best actor on his second nomination. He got a nod last year for "A Single Man."

"I have a feeling my career has just peaked," he joked as he took the Kodak Theatre stage to accept the Oscar. "My deepest thanks to the Academy. I'm afraid I have to warn you that I'm experiencing stirrings somewhere in the upper abdominals which are threatening to form themselves into dance moves."

The actor also thanked the cast and crew of "The King's Speech," including Hooper for "immense courage and clear-sightedness."

Portman, on her second nomination, won the Oscar. She was nominated for supporting actress for "Closer" in 2004.

"This is insane," the 29-year-old pregnant actress said. "And I truly sincerely wish that the prize tonight was to get to work with my fellow nominees. I'm so in awe of you. I'm so grateful to get to do the job that I do. I love it so much."

The actress, who was expecting a child, also thanked her parents who presented at the gala, for giving her life and the opportunity to work at an early age.

Melissa Leo and Christian Bale garnered supporting actress and actor Oscars for their work, respectively.

Melissa Leo, 50, who already had Golden Globe and Screen Actors Guild wins under her belt for her work in boxing flick "The Fighter," still was virtually speechless when she accepted the Oscar for supporting actress.

"Oh, wow. Really, really, really, really, really truly wow," a visibly moving Leo said on stage at the Kodak Theater. "I know there's a lot of people that said a lot of real real nice things to me for several months now, but I'm just shaking in my boots here."

"I want to thank the very most of all, the Academy of Motion Picture Sciences, the Board of Governors, and all their members, whom many of you are here today," she said. "This has been a extraordinary journey in getting to know what the Academy is about and first and foremost, thank you Academy, because it's about selling motion pictures and respecting the work!"

The actress, who won her first Oscar, thanked Alice Ward, the boxing-family matriarch she portrayed in the film, and the entire Ward family, "for opening your hearts to all of us to make this film."

Leo previously got a nod for best actress for "Frozen River" in 2008.

Bale, 37, landed his first Oscar after he was nominated for the honor. He also had Golden Globe and SAG award wins for his role as Dicky Eklund in the gritty movie.

"Bloody hell. What a room full of talented and inspirational people, and what the hell am I doing in the midst of you," he said. "It's such an honor."

Bale, who has a reputation as a sometimes hot-headed co-worker and who was caught on tape verbally berating a crew member on the set of "Terminator Salvation," joked that he would not use the "F-bomb" like Leo did during her acceptance speech.

"I've done that plenty before," he said.

Aaron Sorkin, winning the Oscar for best adapted screenplay for "The Social Network," paid homage to a legendary screenwriter.

"It's impossible to describe what it feels like to be handed the same award that was given to Paddy Chayefsky 35 years ago for another movie with 'Network' in the title," he said.

In best original screenplay category, David Seidler landed an Oscar for his role in "The King's Speech." He joked about claiming the prize in his 70s.

"My father always said to me I would be a late bloomer," he said,drawing laughs from a packed Kodak Theatre crowd. "I believe I am the oldest person to win this particular award. I hope that record is broken quickly and often."

"Toy Story 3" walked away with the Oscar for best animated feature, as widely expected, while the award for animated short went to "The Lost Thing" dealing with a small boy who finds an unusual creature and tries to find a home for it.

Other early awards went to: "Alice in Wonderland" for art direction featuring production design by Robert Stromberg and set decoration by Karen O'Hara; and Wally Pfister for cinematography for "Inception."