Hollywood A-listers are getting ready to lavish awards on Christopher Nolan's atomic blockbuster "Oppenheimer" and party with "Barbie" on Sunday at the Oscars, the biggest night in showbiz.

Nolan's drama about the inventor of the nuclear age, half of last summer's massive "Barbenheimer" phenomenon, is the firm favorite to win the prize for best picture and much more at the star-studded gala.

With an overdue director, stellar cast, commercial and critical success, and urgent subject matter, "there is no justifiable reason to predict anything else," said Hollywood Reporter awards columnist Scott Feinberg.

Variety awards editor Clayton Davis said "Oppenheimer" is the "biggest lock" to win best picture since the final "Lord of the Rings" film two decades ago.

It is tipped to take golden statuettes for best director, supporting actor for Robert Downey Jr., and technical prizes from cinematography and editing to sound and score.

The film has a strong chance at best actor honors for Cillian Murphy, who is locked in a tight race with Paul Giamatti of "The Holdovers," and could claim best adapted screenplay too.

"It just had everything, the scale, the scope, the importance," said one Oscars voter, who asked to remain anonymous as Academy members are instructed not to discuss their ballots.

"This is the year for 'Oppenheimer,'" the voter told AFP.

Elsewhere, the competition for best actress promises to be a nail-biter.

Emma Stone, who previously won an Academy Award for "La La Land," gives a stunning, daring performance in the surreal, Frankenstein-esque "Poor Things."

But Lily Gladstone of "Killers of the Flower Moon" has not just the clout of her director Martin Scorsese, but the weight of history behind her.

She is seeking to become the first Native American to win an acting Oscar.

"Gladstone holds her own against Robert De Niro and Leonardo DiCaprio, these towering actors" in Scorsese's historical crime epic, said the anonymous voter.

Should the two frontrunners cancel one another out, Sandra Hueller of "Anatomy of a Fall" could be "the underdog," the voter added.

The French courtroom thriller is the frontrunner for best original screenplay.

Pink carpet

And what about "Barbie," released on the same weekend last summer as "Oppenheimer," prompting a bizarre and highly memeable double bill that collectively grossed $2.4 billion worldwide?

The surreal feminist comedy is likely to earn technical prizes including costume design, and boasts the two frontrunners for best original song.

Both Billie Eilish's "What Was I Made For?" and the movie's showstopping "I'm Just Ken" will be performed during the Oscars gala.

Supporting actor nominee Ryan Gosling's first-ever live performance of his character's signature power ballad is likely to be a standout moment.

With Margot Robbie nominated as a producer, America Ferrera as a supporting actress, and Greta Gerwig for screenplay, the cast and crew of "Barbie" are expected to turn the Oscars' famous red carpet a bright shade of pink.

Da'Vine Joy Randolph ("The Holdovers") is the firm favorite to win for best supporting actress, while race satire "American Fiction" could dampen the "Oppenheimer" sweep with adapted screenplay honors.

In best documentary, a win for "20 Days in Mariupol" should help redirect attention — however momentarily — to the war in Ukraine.

The United Kingdom is expecting its first-ever best international film Oscar, with Auschwitz drama "The Zone of Interest."

Japanese cinema has "Godzilla Minus One" tipped to win best visual effects, and "The Boy and the Heron" vying for best-animated feature, where it will battle against "Spider-Man: Across the Spider-Verse."

Late-night funnyman Jimmy Kimmel returns to helm the Oscars for a fourth time.

His highly praised hosting last year helped boost ratings back to nearly double their pandemic-era lows.

The 96th Academy Awards will take place in Hollywood on Sunday from 4:00 p.m. (2300 GMT).