Daniel Day-Lewis gave his Oscar chances a welcome boost on Sunday by landing the prize as best actor at the British Academy Film Awards for his searing portrayal of a driven oil prospector in "There Will be Blood."

French actress Marion Cotillard sprung the surprise of the night by scooping the best actress award for her role as singer Edith Piaf in "La Vie En Rose," while the romantic British wartime drama "Atonement" was picked as best film.

Day-Lewis, already hotly fancied to land an Oscar in two weeks' time, fought off tough competition from Hollywood star George Clooney in the legal thriller "Michael Clayton" and Scottish performer James McAvoy for his leading role in "Atonement."

Renowned for his intense preparation for roles, Day-Lewis won a best actor Oscar in 1989 for his moving performance as a man with cerebral palsy in "My Left Foot." The English-born actor who carries an Irish passport famously stayed in character on set even when the cameras were not rolling.

Making a rare sortie into the media spotlight, Day-Lewis told reporters on the BAFTA red carpet, "I'm quite pleased to be part of the circus this year, as it's a good year."

Veteran actress Julie Christie had been odds-on favorite with bookmakers to land the best actress award for playing a woman with Alzheimer's disease in "Away From Her" but lost out to Cotillard.

"Atonement," which had led the field with 14 BAFTA nominations, failed to earn any of the main acting honors but did land the coveted best film Award to give the home crowd something to cheer.

British actress Tilda Swinton was named best supporting actress for her role as a morally corrupt corporate lawyer in "Michael Clayton," while Spanish actor Javier Bardem was crowned best supporting actor for his chilling portrait of a killer in the bleak, modern-day western "No Country for Old Men."

"No Country for Old Men" also won the best director prize for filmmaking brothers Joel and Ethan Coen.

Playwright Ronald Harwood landed the award for best adapted screenplay for "The Diving Bell and the Butterfly," his dramatization of the autobiography of Jean-Dominique Bauby, who was totally paralyzed except for his left eye.

Diablo Cody won the best original screenplay award for "Juno," a teen pregnancy comedy that is also in line for Oscar glory on February 24.