The chain reaction set off by the fusion of "Barbie" and "Oppenheimer" will come to a head this Sunday at the Oscars, where one is expected to own the red carpet, and the other to dominate the awards.

"Oppenheimer" -- Christopher Nolan's epic drama about the father of the atomic bomb, and half of last summer's "Barbenheimer" phenomenon -- is the overwhelming favorite to win best picture honors and much more on Hollywood's biggest night.

The combination of a revered director, unimpeachable cast, box office and critical success, and an urgent subject matter means "there is no justifiable reason to predict anything else," Hollywood Reporter awards columnist Scott Feinberg told AFP.

"It would be an all-time upset if 'Oppenheimer' does not win" best picture, he said.

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

It also has a strong chance at best actor for Cillian Murphy, who is locked in a tight race with Paul Giamatti of "The Holdovers."

And if the film -- based on a Pulitzer Prize-winning biography of J. Robert Oppenheimer -- wins best adapted screenplay, the sweep could be huge.

"I went pretty much all 'Oppenheimer' this year," said one Oscars voter, who asked to remain anonymous as Academy members are instructed not to discuss their ballots.

"It was just such a monumental cinematic achievement... this is the year for 'Oppenheimer,'" the voter told AFP.

Elsewhere, the competition for best actress promises to be a nailbiter.

Emma Stone, who previously won an Academy Award for "La La Land," is considered one of the finest actors of her generation. She gives a stunning, brave performance in "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, and she was the heart of the movie," said the anonymous voter.

Should the two frontrunners cancel one another out, "you cannot underestimate Sandra Hueller... she is the underdog," the voter added.

Hueller stars in French courtroom thriller "Anatomy of a Fall," which 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 meme-able double bill that collectively grossed $2.4 billion worldwide?

The surreal feminist comedy is unlikely to leave the Oscars empty-handed.

As well as technical prizes like costume design, it boasts the two frontrunners for best 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 the latter power ballad is likely to be a standout moment.

With Margot Robbie nominated as a producer, America Ferrera as 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.

Read more

Spielberg, Gosling, Blunt, and Ferrera in third list of Oscars presenters

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