Marion Cotillard wore a cream Jean-Paul Gaultier gown - Photo : Timothy A. Clary/AFP

HOLLYWOOD, Feb 24, 2008 (AFP) - The world's most glamorous fashion show got underway here Sunday as movie stars and celebrities dazzled the Oscars red carpet less shortly before the 80th Academy Awards.

Thick clouds and sporadic rain prompted Oscars organisers to cover the red carpet with a protective canopy as VIPs began to arrive for the ceremony at the Kodak Theatre, which gets underway at around 5:00 pm (0100 GMT).

Among the first arrivals were Hollywood heart-throb George Clooney as well as German supermodel Heidi Klum and her singer husband Seal.

Clooney, who was accompanied by partner Sarah Larson, is one of the contenders for the best actor Oscar, where he is nominated for his role in the legal thriller "Michael Clayton."

"It's a fun one this year, because it's a film we're all really proud of. So it's easy to be here," Clooney told a reporter, laughing off reports he had recently purchased a Malibu beach house as a Valentine's Day gift.

"I haven't heard that one before. I wasn't even in Malibu on Valentine's Day. We were in Vegas."

Another arrival was "Gone Baby Gone's" Amy Ryan, a first-time nominee looking striking in a navy Calvin Klein gown.

"This is magic it's just a thrill to be here," said Ryan, nominated in the best supporting actress category for her performance in Ben Affleck-directed drama where she plays a drug addict whose daughter is kidnapped.

Irish teenager Saoirse Ronan meanwhile, nominated for best supporting actress for her role in the British historical drama "Atonement", was chaperoned by her father.

The 13-year-old actress, who missed out on attending the Golden Globes earlier this year after it was cancelled due to the Hollywood writers strike, wore an emerald Alberta Feretti gown.

"I never even thought I'd say an Italian name, let alone wear a dress by an Italian designer," Ronan said.

French star Marion Cotillard -- one of the favorites to win the best actress Oscar for her portrayal of tragic chanteuse Edith Piaf in "La Vie En Rose" -- wore a cream Jean-Paul Gaultier gown.

"I'm very excited, very proud, very honored to be amongst such amazing actresses. I'm having a unique time here," Cotillard said.

Earlier, two auditors from accounting firm PriceWaterhouseCoopers carrying the envelopes which bear the identities of Sunday's Oscar winners were among the first arrivals.

Accountants Rick Rosas and Brad Oltmanns are the only people in the world to know the identities of the Oscar-winners before the awards start.

A steely security blanket has been draped across Hollywood, with around a dozen streets surrounding the Kodak Theatre closed to the public.

Several hundred police were manning barricades, conducting identity checks and vehicle searches -- including celebrities' limos -- as authorities leave nothing to chance.by Philippa Leach