Old-style Hollywood glamour swept onto the Oscars' red carpet on Sunday, with designer-clad movie stars and nervous nominees dripping in precious stones, reigniting a classic regal look.

Megastars such as Nicole Kidman and Meryl Streep, Oscar nominees Reese Witherspoon, Charlize Theron, Keira Knightley and Rachel Weisz, as well as actresses Jennifer Aniston, Salma Hayek and Australia's Naomi Watts, hit the famous flashbulb-lit catwalk in dazzling style.

The galaxy of radiant stars was met by the screams of around 300 fans who had won lottery tickets for seats on the bleachers along the red carpet, and by a barrage of questions from hundreds of journalists.

Tinseltown's leading men were also dressed to kill, most of them in classic black tuxedos and white shirts, except for US filmmaker Tim Burton, who defied tradition with a red shirt and straight tie emblazoned with a skull and crossbones.

Heartthrob George Clooney was joined on the red carpet by such stars as Australian Oscar hopeful Heath Ledger, one of the gay cowboys of the favourite to dominate the Oscars, "Brokeback Mountain"; Ledger's fellow cowboy and best supporting actor nominee Jake Gyllenhaal; and Matt Dillon, nominated for his supporting role in "Crash."

Also strutting their stuff were "Walk the Line" Oscar hopeful Joaquin Phoenix, former "Speed" co-stars Sandra Bullock and Keanu Reeves, supporting actor nominee Paul Giamatti, Australian actor Eric Bana, Will and Jada Smith, 1940s star Jane Russell and superstar Jack Nicholson.

The big man of the night, triple nominee and veteran screen heartthrob Clooney, 44, arrived alone, dressed in his faithful 10-year-old tuxedo, cracking irreverent jokes about his competition for the best director award.

"I don't like anybody else here," he said. "I'll tell you right off the bat.

"You know this Ang Lee guy, I don't like him -- I think he's a Communist," he said of the "Brokeback Mountain" filmmaker.

Clooney -- nominated as best director and screenwriter for his political drama "Good Night, and Good Luck," about repression during the 1950s US Communist witch hunt -- won the best supporting actor Oscar for "Syriana."

British best supporting actress winner Weisz was one of the first arrivals, wearing a very elegant black satin Narciso Rodriguez dress and diamond Chopard earrings.

Weisz, 34, won the Oscar for her turn as a crusading activist fighting pharmaceutical-industry wrongdoing in Kenya in "The Constant Gardener."

Fellow Briton, best actress nominee Knightley, 20, up for "Pride and Prejudice," was stunning in an off-the-shoulder burgundy Vera Wang gown and a 1960s Bulgari jewelled necklace.

"It's crazy, quite astonishing," she said of the pandemonium and excitement on the red carpet.

Kidman, the 2003 best actress winner, was elegant in a strapless, heavily-embroidered cream Balenciaga gown, while South African former Oscar winner Theron, one of this year's best actress nominees, was wearing a black gown with matching pearls.

Australia's biggest hope of the night, the 26-year-old Ledger, who is up for best actor for Lee's "Brokeback Mountain," arrived with his fiancee and "Brokeback" co-star Michelle Williams, who was wearing a bright mustard-coloured chiffon dress.

Gyllenhaal, a best supporting actor nominee, arrived, saying he was a little tired of being asked what it was like to kiss Ledger on screen.

"The kissing thing is a little bit much now -- it's unfortunate, too, because we all have stock answers now, too, so it's not great for the interviewer, either; things like, 'Yeah, it's fine; it's like kissing a girl.'"

Witherspoon, favoured to win the best actress Oscar for her singing role opposite Phoenix in "Walk the Line," was radiant in pink and was escorted by husband Ryan Phillippe.

"I overcame a lot of the fear I had, and that was a huge accomplishment for me," she said of her role as June Carter Cash.

Helena Bonham Carter, who arrived with Tim Burton, wore an electric-blue silk-satin Vivienne Westwood gown, to counterbalance Burton's offbeat look.

Triple Oscar winner Jack Nicholson, the most nominated man in Oscars history, with 12 nominations to his credit, arrived with his children to present an award.

"Munich" star and fellow presenter Bana arrived with his wife, while another famous Aussie, Watts, star of Peter Jackson's "King Kong," turned up wearing a beige Givenchy gown to present an award.

Aniston, the former Mrs Brad Pitt, wore a Rochas gown and Bulgari jewelry, while Mexican-born actress Salma Hayek was in a sultry blue Versace number.

Among the first to show up were the two men harbouring Tinseltown's biggest secret: the auditors from accounting firm PriceWaterhouseCoopers who tallied the ballots, slipped the names of the winners into the famed envelopes and brought them to the ceremony in two briefcases.