(From left) Benny Safdie, Cillian Murphy, Robert Downey Jr., Josh Hartnett, Alden Ehrenreich, Casey Affleck, Emily Blunt and Kenneth Branagh, winner of the Outstanding Performance by a Cast in a Motion Picture award for "Oppenheimer", pose in the press room during the 30th Annual Screen Actors Guild Awards at the Shrine Auditorium in Los Angeles, Feb 24, 2024. (PHOTO / AFP)

LOS ANGELES - Historical epic Oppenheimer picked up more prizes on Saturday at Hollywood's Screen Actors Guild Awards, bolstering the movie's chances to score the best picture trophy at next month's Oscars.

The film about the race to build the first atomic bomb took the top honor - best movie cast - handed out by members of the SAG-AFTRA actors union at a red-carpet ceremony in Los Angeles.

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

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

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.

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

ALSO READ: 'Oppenheimer' triumphs at BAFTA Film Awards with most win

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."

Da'Vine Joy Randolph won supporting actress for playing a grieving mother in The Holdovers. "How lucky are we to get to do what we do. I wake up every day overwhelmed with gratitude to be a working actor," Randolph said.

(From left) Kenneth Branagh, David Krumholtz, Emily Blunt, Alden Ehrenreich, Robert Downey Jr., Josh Hartnett, Cillian Murphy, Casey Affleck, and Benny Safdie accept the award for outstanding performance by a cast in a motion picture for "Oppenheimer" during the 30th annual Screen Actors Guild Awards on Feb 24, 2024, at the Shrine Auditorium in Los Angeles. (PHOTO / AP)

The awards streamed live on Netflix for the first time, part of the company's efforts to expand its live programming.

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

ALSO READ: 'Oppenheimer' leads BAFTA Film Awards nominations

"It is especially meaningful to be here with us all together again, for this occasion, after going though a very difficult time with the strike," actor Idris Elba said in opening remarks.

Lily Gladstone accepts the award for outstanding performance by a female actor in a leading role for "Killers of the Flower Moon" during the 30th annual Screen Actors Guild Awards on Feb 24, 2024, at the Shrine Auditorium in Los Angeles. (PHOTO / SP)

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

"I am so honored to be in this community," White said. "I wanted to be part of this my whole life. I had no backup plan."

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

Da'Vine Joy Randolph, winner of the Outstanding Performance by a Female Actor in a Supporting Role award for 'The Holdovers', poses in the press room during the 30th Annual Screen Actors Guild Awards at Shrine Auditorium and Expo Hall on Feb 24, 2024 in Los Angeles, California. (PHOTO / AFP)

Elizabeth Debicki, who played Princess Diana in Netflix series The Crown, won best TV drama actress. 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!"

READ MORE: 'Oppenheimer', 'Poor Things' win major prizes at Golden Globes

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