Historical epic Oppenheimer has picked up more prizes at Hollywood’s Screen Actors Guild (SAG) Awards, as Australia’s Elizabeth Debicki won a trophy for her role as Diana, Princess of Wales in The Crown.

The film about the race to build the first atomic bomb took the top honour – best movie cast – bolstering the movie’s chances to score the best picture trophy at next month’s Oscars.

The award was handed out by members of the SAG-AFTRA actors union at a red-carpet ceremony in Los Angeles on Saturday night.

Cillian Murphy, who played scientist J Robert Oppenheimer, won best movie actor, and co-star Robert Downey Jr best supporting actor.

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Irish actor Murphy said he took up the profession after trying to make a career as a musician and often felt like an “interloper”.

“This is extremely special to me because it comes from you guys,” Murphy told his fellow actors as he accepted his award.

Earlier, Debicki won the award for outstanding performance by a female actor in a drama series, beating The Morning Show‘s Jennifer Aniston, Bella Ramsey from The Last of Us, The Diplomat‘s Keri Russell and Succession‘s Sarah Snook.

“Truly, I was not expecting this,” the 33-year-old said.

“The women in my category, I watch with total awe and I learn how to do my craft watching you. So being nominated next to you is incredible.”

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SAG-AFTRA’s choices are closely watched because actors form the largest group of voters for the Academy Awards, the film industry’s top prizes.

At the moment Oppenheimer appears unstoppable. Director Christopher Nolan’s drama already has claimed trophies at the Golden Globes, the British Academy Film Awards and other ceremonies.

Honours from the Producers Guild of America, another key predictor of Oscars success, will be announced on Sunday.

In other SAG accolades, the best actress trophy went to Lily Gladstone, star of Killers of the Flower Moon.

Gladstone played a member of the Osage Native American community that suffered a string of murders in 1920s Oklahoma over their oil-rich land.

“My friends, fellow actors, I feel the good in what you have done,” Gladstone said. “We bring empathy into a world that so much needs it.”

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Da’Vine Joy Randolph won supporting actress for playing a grieving mother in The Holdovers.

SAG-AFTRA staged a four-month strike against Hollywood studios last year to fight for higher pay and protections from artificial intelligence.

In television categories, FX restaurant dramedy The Bear claimed best cast in a TV comedy and acting honours for stars Jeremy Allen White and Ayo Edebiri.

HBO’s Succession secured best TV drama cast for its final season about the battle for control of a family’s media dynasty.

The Last of Us star Pedro Pascal was named best actor in a TV drama and appeared stunned when he walked on stage.

“I’m a little drunk,” Pascal said as he held his trophy. “I thought I could get drunk … I’m making a fool of myself. Thank you so much!”

SAG-AFTRA also handed out a lifetime achievement honour to Barbra Streisand, the award-winning actor, producer, director, singer and writer.

-Reuters