LOS ANGELES - Bedecked in gowns, tuxedos and even shorts, the world's top actors and actresses strode down the red carpet at the Academy Awards on Sunday with all eyes on the cliffhanger best picture race between frontrunners "12 Years a Slave" and "Gravity."

As if on cue, the sun came out after four days of heavy rain just before the first movie stars exited their limos in a mix of outfits as diverse as the films competing for the Oscars, Hollywood's top honors.

Amy Adams, best actress nominee for her role as a con woman in "American Hustle," graced the red carpet in a strapless navy gown. British best actor nominee Chiwetel Ejiofor, who plays the slave Solomon Northup in "12 Years a Slave," showed up in the classic tuxedo, while singer Pharrell Williams wore a Lanvin tux with shorts rather than trousers.

Another best actor nominee, 77-year-old Bruce Dern, star of "Nebraska," came on the arm of his daughter, Laura Dern, dressed in a pastel pink gown, who said "I'm very moved to get to celebrate him and be here."

The 86th annual Academy Awards will be hosted by comedian and day-time talk show host Ellen DeGeneres, who producers are banking on to deliver an entertaining yet tasteful three-hour show after critics widely panned last year's ceremony and host Seth MacFarlane's provocative humor.

One of the features of the night will be a tribute to "The Wizard of Oz" for its 75th anniversary and star Judy Garland's children, including singer and actress Liza Minnelli in a blue pant suit, were in attendance.

Sunday was the culmination of an unusually long awards season, extended by the Winter Olympics, and for many of the nominees it spelled the end to months of campaigning and years of work on a film.

One of the most notable names on the awards season fashion radar this year, best supporting actress nominee Lupita Nyong'o, wore a blue custom-made Prada.

"It's a blue that reminds me of Nairobi and I wanted to have a little bit of home," said the Kenyan actress who plays the hardworking slave, Patsey, in "12 Years a Slave."

The Academy of Motion Picture Arts and Sciences could make history this year if it chooses "12 Years a Slave" for best picture. It would be the first time that the top film honor goes to a movie by a black director in the 86 years of the Oscars.

While British director Steve McQueen's brutal slavery drama is the presumed frontrunner for best picture, the groundbreaking "Gravity" with its technical achievements lurks just behind.

Apart from the best picture race, it may be a night of predictable outcomes, from "Gravity" filmmaker Alfonso Cuaron's likely win of the best director statuette to the virtual shoo-in of "Frozen" for best animated film. The four acting races might also be foregone conclusions.

Scattered awards

This year's Oscars celebrate what is widely regarded as one of the most high quality years in film and performances in recent memory. That means that awards are likely to be scattered widely as the 6,000-plus members of the Academy seek to reward as many films as possible with the famed golden statuettes.

Among the other best picture contenders is 1970s crime caper "American Hustle" from director David O. Russell, which scored 10 nominations. For the second year in a row, Russell has achieved the rare feat of having his actors nominated in all four acting categories. Martin Scorsese's "The Wolf of Wall Street," a tale of financial greed and excess, has also been a hit with audiences and critics.

A total of nine films are competing for best picture, including Somali piracy thriller "Captain Phillips," the adoption drama "Philomena," the heartland comedy "Nebraska," the computer-age romance "Her," and the AIDS activist biopic "Dallas Buyers Club."

The acting categories may yield few surprises on Sunday. Cate Blanchett is heavily favored to win her first best actress Oscar for her portrayal of the disgraced socialite in Woody Allen's "Blue Jasmine."

Matthew McConaughey is also a solid bet for best actor for his role as the unlikely AIDS activist in "Dallas Buyers Club," for which he lost some 50 pounds (23 kg) while co-star Jared Leto is tipped for best supporting actor.

Of the four races, the best supporting actress race might be the most compelling. Newcomer Nyong'o is favored but she faces a serious challenge from Jennifer Lawrence as the loopy housewife in "American Hustle."

Among the presenters will be Hollywood power couple Angelina Jolie and Brad Pitt as well as Sidney Poitier on the 50th anniversary of his best actor win for "Lilies of the Field," the first Oscar in that category for an African American.

The show will be broadcast live in the United States on ABC television starting at 5:30 p.m. PST/8:30 p.m. EST and to 225 countries around the world.