Dark comedy "Birdman" boosted its Oscars hopes Sunday after landing the top prize at the 21st Screen Actors Guild Awards, a barometer of likely success at the all-important Academy Awards.

The film about a washed up superhero movie star attempting to revive his career on Broadway took the SAG equivalent of the Oscars best picture with victory in the outstanding performance by a cast category.

The comedy emerged victorious ahead of coming-of-age drama "Boyhood," Wes Anderson's screwball caper "The Grand Budapest Hotel," World War II drama "The Imitation Game" and the Stephen Hawking biopic "The Theory of Everything."

The honor for "Birdman" came just 24 hours after Mexican director Alejandro Gonzalez Inarritu's film scooped the top prize at the Producers Guild of America awards, another significant Oscars bellwether.

The victory leaves the film on pole position heading into next month's Academy Awards, which will be handed out in Hollywood on February 22.

In the acting honors, Britain's Eddie Redmayne thrust himself into Oscars contention by winning the best actor award for his portrayal of stricken physicist Hawking in "The Theory of Everything."

Redmayne, 33, beat out competition from Michael Keaton ("Birdman"), seen by many as a favorite, Benedict Cumberbatch ("The Imitation Game"), Steve Carell ("Foxcatcher") and Jake Gyllenhaal ("Nightcrawler").

In his acceptance speech, Redmayne paid tribute to the wheelchair-bound Hawking, who suffers from amyotrophic lateral sclerosis (ALS).

"Thank you for allowing someone who gave up science when they were 14 years old to enter your orbit," Redmayne said.

"And thank you for reminding me of the overwhelming power of the will to love and the will to live every second of your life as fully and as passionately as possible."

Perennial Hollywood favorite Julianne Moore, who has swept most of the awards season honors for her portrayal of a woman suffering from Alzheimer's in "Still Alice," took the best actress prize.

"When I was 17 and I decided I wanted to be an actor it didn't seem possible because I'd never met a real actor," Moore said. "So I want to say to all you kids in drama club: You guys are the real actors."


More wins for 'Boyhood'


A star-studded night at Los Angeles's Shrine Auditorium largely went to form, with veterans J.K. Simmons and Patricia Arquette scoring the first major film awards of the evening with wins in the supporting categories.

Veteran Simmons cemented his status as the overwhelming Oscars supporting actor favorite by picking up the corresponding SAG award for his portrayal of a fearsome music teacher in the acclaimed indie drama "Whiplash."

Simmons, 60, who has already won a Golden Globe award for the performance, dedicated his win to all members of his profession.

"I feel like all of us are supporting actors," he said. "Each of us is essential, crucial, because if there's one false moment the train comes off the rails."

Others nominated in the category were Robert Duvall ("The Judge"), Ethan Hawke ("Boyhood"), Edward Norton ("Birdman") and Mark Ruffalo ("Foxcatcher").

Arquette scooped her award for her performance in "Boyhood," director Richard Linklater's 12-year labor of love.

The 46-year-old paid a moving tribute to her late mother Olivia -- who died in 1997 from breast cancer -- after collecting her award.

"You are my hummingbird, you are always with me," she told the audience.

Elsewhere Sunday, Netflix prison comedy-drama "Orange Is The New Black" and British stately home drama "Downton Abbey" were the big winners in the television categories.

"Orange Is The New Black" took home the comedy ensemble honors and outstanding actress award for Uzo Aduba.

"Downton Abbey" meanwhile took the coveted outstanding ensemble drama award.