Daniel Day-Lewis has made Oscar history after becoming the first man to win the best actor trophy three times.
The British-born actor was honoured for his portrayal of President Abraham Lincoln in Steven Spielberg's historical drama.
He spent a year preparing for the role and, in his customary method, remained in character during the production.
Accepting his Oscar from Meryl Streep, Day-Lewis said: "I really don't know how any of this happened, I do know I've received more than my fair share of good fortune in my life."
He joked Streep had been the first choice to play Lincoln and he had been committed to play Margaret Thatcher - the role that won Streep an Oscar last year - before tearfully thanking his mother.
He previously won in 1989 for My Left Foot and in 2007 for There Will Be Blood.
It was a good night for British talent with Adele winning the Oscar for best original song for her Bond theme Skyfall.
The tearful singer thanked her songwriting partner Paul Epworth for "believing in me all the time, and my man, I love you baby".
She wowed the audience of A-listers in the Dolby Theatre with her first ever live performance of the 23rd Bond film's title track.
Ben Affleck's Iran hostage thriller, Argo, won the Oscar for best picture, despite the star being snubbed in the best director category.
The nominees for best film were introduced by First Lady Michelle Obama from the White House, before she named Argo as the winner.
Affleck, who also starred in the film, paid tribute to the "genius" Spielberg whose film, Lincoln, lost out in the category.
Referring to his success with 1997's Good Will Hunting, he said: "I never thought I would be back here and I am because of so many of you who are here tonight."
He added: "It doesn't matter how you get knocked down in life, all that matters is that you get up."
It was the first time since Driving Miss Daisy in 1990 that a film won the top prize at the Oscars without its director also being nominated.
The show's host Seth MacFarlane, the man behind hit cartoon Family Guy, started proceedings by poking fun at the Academy for not nominating Affleck, saying the plan was "so top secret the film's director is unknown to the Academy".
Taiwanese director Ang Lee picked up the statuette for best director for Life of Pi, beating Spielberg who many expected would collect the award for Lincoln. Lee collected the same award for Brokeback Mountain in 2005.
In a night that was otherwise short on shocks Jennifer Lawrence claimed the best actress gong for Silver Linings Playbook.
The 22-year-old fell as she climbed the steps to the stage to claim her prize.
Some had predicted the award would go to French actress Emmanuelle Riva who starred in Amour and at 86 was the oldest woman ever to be nominated. She won a Bafta award earlier this month for the role.
Anne Hathaway picked up the best supporting actress statue for her role in the musical Les Miserables.
The star, who only featured as Fantine in the film for around 15 minutes, fought back tears as she said "it came true" and thanked her husband and everyone who worked on the film.
She had been widely predicted to win the award in a tough category where Sally Field, Helen Hunt, Amy Adams and Jacki Weaver were also nominated.
Christoph Waltz won the first award of the night, best supporting actor, for his role in Django Unchained.
Waltz offered thanks to his character and "to his creator and the creator of his awe-inspiring world, Quentin Tarantino".
It was the second time in three years he has won the category - his first Oscar was for his role in Tarantino's Inglourious Basterds.
Waltz beat off stiff competition from Alan Arkin, Robert De Niro, Philip Seymour Hoffman and Tommy Lee Jones.
Tarantino went on to collect the prize for best original screenplay.
Brave, the Scottish story of a rebellious, red-headed princess, won the Oscar for best animated feature.
Amour, a French-language film about an elderly couple won best foreign language film which was accepted by its Austrian director Michael Haneke.
Skyfall also won the trophy for best sound editing, which was tied with Zero Dark Thirty. It is only the third time in Oscar history that winners have been tied.
The night of British success started with Jacqueline Durran winning for her costume design on Anna Karenina and the make-up and hairstyling award went to Lisa Westcott and Julie Dartnell for Les Miserables.
The presentation of awards was broken up by a series of musical performances including Catherine Zeta-Jones singing All That Jazz from Chicago and Jennifer Hudson performing I'm Telling You from Dreamgirls.
A tribute to the Bond films and music made up of classic clips of 007's adventures was introduced by one-time Bond girl Halle Berry.
And 76-year-old Dame Shirley Bassey took to the stage in a gold dress to sing Goldfinger which received a standing ovation.
But it was a medley of Les Miserables songs sung by the cast that left the audience with goosebumps.