updated 12:24 a.m. ET Feb. 25, 2008

LOS ANGELES - Marion Cotillard did more than become a new Academy Awards darling on Sunday. She also denied a long-established one.

With a phenomenal performance as singer Edith Piaf in “La Vie En Rose,” Cotillard pulled an upset win for best actress over Julie Christie, who had been the favorite to claim a second Oscar 42 years after she won for “Darling.”

“Wow. Well, I’m speechless now,” a tearful Cotillard said, her French-accented voice quivering as she accepted the award. “It is true ... angels in this city. Thank you so, so much.”

Backstage, her delight was even less restrained.

“It feels so good. I’m totally overwhelmed with joy and sparkles and fireworks and everything which goes like bom-bom-bom,” Cotillard said.

The French actress has appeared in such Hollywood films as “Big Fish” and “A Good Year,” but generally was unknown to U.S. audiences until “La Vie En Rose.”

Cotillard, 32, won out over a strong field of actresses from around the globe. Along with Christie, who is British, the nominees were Cate Blanchett of Australia for “Elizabeth: The Golden Age,” American Laura Linney for “The Savages,” and Canada’s Ellen Page for “Juno.”

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The best-actress category had been considered a two-woman race between Cotillard and Christie, with the latter the front-runner for “Away From Her,” in which she gives a heartbreaking performance as a woman succumbing to Alzheimer’s.

Born in Paris, Cotillard grew up in a stage family, with both parents actors. She performed in plays starting at age 3 or 4, but acted only occasionally during childhood, settling on a career in drama in her late teens.

Cotillard found steady work in French film and television. Her credits include producer Luc Besson’s action comedy “Taxi” and its sequels and Jean-Pierre Jeunet’s acclaimed drama “A Very Long Engagement,” the latter earning her the supporting-actress prize at the Cesars, France’s equivalent of the Oscars.

Two days before her Oscar triumph, Cotillard won the best-actress Cesar for “La Vie En Rose.”

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With song-and-dance films making a comeback, Cotillard was the latest in a string of performers winning for music-themed pictures, including Jennifer Hudson for “Dreamgirls,” Reese Witherspoon for “Walk the Line,” Catherine Zeta-Jones for “Chicago” and Jamie Foxx for “Ray.”

Like Foxx, Cotillard had to learn the fine art of lip-synching, mimicking Piaf’s expressions and body language while mouthing along to tracks prerecorded by French singer Jil Aigrot, who re-created Piaf’s distinctive warble.

Playing Piaf from her fiery teens through her fragile 40s, Cotillard offered a remarkable embodiment of the singer, who rose from a guttersnipe belting out tunes in the streets to become an international star in the 1930s, ’40s and ’50s. Piaf died in 1963 at age 47.

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“I really dedicated my life to the movie and to Edith Piaf for a few months,” Cotillard said backstage.

“My aim was to understand her. To understand her heart, her soul. And so I went as deep as I could. I tried to do my best to find her inside me. And but it was not so hard, because I really love her.”

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