Dark comedy "Birdman" topped nominations for the Screen Actors Guild (SAG) awards announced Wednesday, getting an Oscars boost as Hollywood's awards race gets into high gear.

"Birdman" -- the tale of a washed-up superhero movie star (former "Batman" Michael Keaton) trying to revitalize his career -- scored four nominations: best actor, best supporting actor and best supporting actress, along with a nod for best ensemble.

Coming-of-age drama "Boyhood," the Stephen Hawking biopic "The Theory of Everything" and "The Imitation Game," the story of World War II codebreaker Alan Turing, each won three nods.

All four films were nominated for best overall cast, along with quirky comedy "The Grand Budapest Hotel."

Britain's Benedict Cumberbatch meanwhile scored a hat trick of acting nominations, including two for "The Imitation Game" and one for hit TV series "Sherlock."

The SAG nominations are the first major awards announcement of Hollywood's annual race for trophies and glory -- a clutch of red-carpet ceremonies that climaxes with the Academy Awards on February 22.

Golden Globe nominations are due on Thursday.

The SAG awards -- which will be given out in Los Angeles on January 25 -- are often an early indication of Oscars hopes, as members of the actors union represent some 20 percent of the 6,000-odd voting members of the Academy of Motion Picture Arts and Sciences.

"Birdman" -- which has won rave reviews for Keaton -- also topped nominations for the Independent Spirit awards announced last month with six nods.


'Cooper, Chastain snubbed'

Among those snubbed by voters were Bradley Cooper in Clint Eastwood's "American Sniper," Jessica Chastain in "A Most Violent Year," and the well-reviewed Martin Luther King historical drama "Selma."

All of those movies are set for release later this month.

For best actor, Keaton is up against Cumberbatch ("The Imitation Game"), Steve Carell ("Foxcatcher"), Eddie Redmayne ("The Theory of Everything"), and Jake Gyllenhaal for "Nightcrawler."

"The Theory of Everything" also scored a best actress nod for Felicity Jones as Hawking's wife Jane in the tale of the groundbreaking physicist's early life and descent into disability with motor neuron disease.

She faces fellow nominees Jennifer Aniston ("Cake"), Julianne Moore ("Still Alice"), Rosamund Pike ("Gone Girl") and Reese Witherspoon ("Wild").

In the best supporting actor category, "Boyhood" co-star Ethan Hawke is up against veteran Robert Duvall ("The Judge"), Mark Ruffalo ("Foxcatcher"), J.K. Simmons ("Whiplash") and Edward Norton ("Birdman").

For best supporting actress, Patricia Arquette ("Boyhood") is up against Keira Knightley ("The Imitation Game"), Meryl Streep ("Into the Woods"), Naomi Watts ("St Vincent") and Emma Stone ("Birdman").

The movie nominations, accompanied by shortlists in eight TV categories, were announced at a pre-dawn ceremony in Los Angeles by actors Ansel Elgort and Eva Longoria.


'Modern Family' tops TV nods

On the small screen, "Modern Family" scored the most nominations with four, followed by "Boardwalk Empire," "Game of Thrones," "Homeland" and "House of Cards" with three apiece.

"Modern Family" won nods for best comedy series as well as acting nominations for Julie Bowen, Ty Burrell and Eric Stonestreet.

For best drama ensemble, the shortlist includes "Boardwalk Empire," "Downton Abbey," "Game of Thrones," "Homeland" and "House of Cards."

The Golden Globe nominations are set to be announced early Thursday by the Hollywood Foreign Press Association (HFPA).

Although more high-profile than the SAGs, the Golden Globes are seen as less of an indicator of Oscars glory, as a relatively small group of non-US journalists chooses the winners, rather than the industry itself.