Oscars host Seth MacFarlane kicked off an unpredictable 85th Academy Awards show Sunday, with Iran hostage drama "Argo" vying to beat Steven Spielberg's "Lincoln" on Hollywood's biggest night.
The star-studded and heavily musical show was preceded by a two-hour A-list fashion parade on the red carpet, with a healthy serving of old-school Hollywood glamour on display.
"Family Guy" creator MacFarlane started with a joke about "Argo" director Ben Affleck, who was nominated for best film but failed to win a best director nomination, quipping that he was "unknown to the Academy."
Among those talking on the Dolby Theatre red carpet was Jessica Chastain, nominated for best actress for Osama bin Laden manhunt movie "Zero Dark Thirty," who played down her hopes for the evening.
"I'm not going to win the Oscars tonight. I just don't think it's my year," Chastain, in a strapless beaded flesh-colored Armani gown, told CNN, saying she was wearing a "Happy birthday, Mr President" kind of dress a la Marilyn Monroe.
Chastain's main rival, "Silver Linings Playbook" star Jennifer Lawrence, strutted her stuff in a strapless cream Dior gown with a full puffy skirt.
"This was such a passion project for all of us," she told E! television, referring to the romantic comedy with an edge that earned a total of eight nominations, including one for best picture.
In a heavily musical show, British songstress Adele was to sing 007 theme "Skyfall" as part of a segment feting 50 years of Bond films -- and legendary diva Barbra Streisand will give her first Oscars performance for 36 years.
Affleck -- who would be the first person to win best picture without being nominated as director since "Driving Miss Daisy" in 1990 -- got a diplomatic boost Saturday when new US Secretary of State John Kerry tweeted best wishes.
"Good luck @BenAffleck and #Argo at the Oscars. Nice seeing @StateDept & our Foreign Service on the big screen.-JK," wrote Kerry, referring to the film's plot about an audacious CIA plot which rescued six US diplomats from Tehran.
Spielberg, bidding for his first best picture Oscar since "Schindler's List" in 1994, tops the nominations with 12 nods for "Lincoln" -- but "Argo" has cleaned up in Hollywood's awards season so far, despite having only seven.
Although he started the season two months ago as the favorite, Spielberg may have to settle Sunday for the best director award -- one that Affleck cannot beat him to, having not been nominated in the category, in a perceived snub.
One near-certainty is that "Lincoln" star Daniel Day-Lewis will be named best actor, a record third for the British-Irish actor after wins in 1990 for "My Left Foot" and in 2008 for "There Will Be Blood."
For best actress the early favorite was Chastain, but the clever money is now on Lawrence -- barring an upset win by French star Emmanuelle Riva for her turn in "Amour," on her 86th birthday.
The best supporting actress race is more open, although Anne Hathaway is probably still the frontrunner for her heart-wrenching turn in "Les Miserables," which is also nominated for best picture.
The most unpredictable race of all is perhaps for best supporting actor, with Hollywood legend Robert De Niro tipped by some for playing Bradley Cooper's father in "Silver Linings Playbook."
De Niro played his card close to his chest on the red carpet Sunday, while praising Cooper. "Bradley is a very smart, compassionate young man, and he cares about what he's doing -- and he likes me!" the veteran said.
On the foreign front, the clear frontrunner is "Amour," which won the Palme d'Or at last year's Cannes Film Festival for its heart-wrenching portrayal of an elderly couple coping with encroaching physical and mental illness.
The best animated feature contest is widely seen as a battle between Scottish-themed princess adventure "Brave" and "Wreck-It Ralph," about a video game villain fed up with being the bad guy.
On the eve of the Oscars, "Silver Linings Playbook" got a publicity boost Saturday when it was named best film at the Independent Spirit Awards, as well as winning the best actress and best director prizes.