Excitement builds on Oscars red carpet

EXCITEMENT was rippling through Hollywood as the first wave of Oscars guests began to arrive on the red carpet for the 82nd Academy Awards.

Australian actor Sam Worthington - the star of science-fiction blockbuster Avatar - was among the early arrivals as the parade of A-listers got under way at the Kodak Theatre.

A torrential downpour greeted guests, who were shielded from the rain by a protective canopy.

Worthington meanwhile admitted that the glitz and glamour of the Oscars was a far cry from the early stages of his career.

"I was living in a car," he joked, saying he was hoping attendance at the Oscars would boost his career prospects.

"I just need another job," Worthington told E! television. "This is all part of it. You put your monkey suit on and try and get another job."

Meanwhile Up In the Air star Anna Kendrick, nominated for best supporting actress, revealed she had suffered a last minute wardrobe crisis before finally settling on her pink gown.

"I never thought I would wear pink," Kendrick said. "It was just the right dress."

Another best supporting actress nominee, comedienne Mo'Nique, said she felt privileged to be part of the awards hoopla.

"I'm honoured, I'm appreciative," said Mo'Nique, who plays an abusive parent in the harrowing drama Precious.

"I'm honoured for the whole process for what this fantasy land is. It's changed my life inwardly."

The Oscars ceremony gets under way about 1pm (AEDT).

Avatar director James Cameron arrived flourishing a bright blue pocket handkerchief inspired by the blue-skinned Na'vi aliens who are the heroes of his film.

"It's a little Na'vi blue," said best director nominee Cameron, adding that he had not expected his film - which has earned a staggering $US2.5 billion ($A2.76 billion) worldwide - to emerge as the highest-grossing film ever.

"We thought we were going to make some money but not nearly as much as we did," he said. "I'd say we went three times the amount we thought we'd make."

Cameron also played down any suggestion of a "Battle of the Exes" in the best director race, where his ex-wife Kathryn Bigelow is also nominated, saying he was "proud" of his former spouse's success.

"It's the media trying to apply a narrative from the outside. We don't feel any sense of competition. We're friends," Cameron said.

"She saw Avatar five times."

Meanwhile Canadian actor Ryan Reynolds said he was hoping that his friend and The Proposal co-star Sandra Bullock would clinch the best actress Oscar for her performance in The Blind Side.

"Everyone loves a good story and I just think Sandy winning is a fantastic story because it couldn't happen to a nicer person," Reynolds told E! television.

"It feels like your good buddy just got drafted to the NBA."