The cast of 1970s crime caper American Hustle have taken the top prize at the Screen Actors Guild awards.
Representing his co-stars, Robert De Niro, Jennifer Lawrence, Amy Adams and Christian Bale, actor Bradley Cooper praised film director David O Russell.
"He is an actor's director," he said. "That notion is tossed around. He is the embodiment of it."
As actors form the biggest voting bloc in the Oscars, the SAG awards are seen as a key indicator for that ceremony.
Last year, the guild chose hostage drama Argo for its top honour, with that film going on to receive the Academy Award for best picture.
However, this year's field is more competitive - with 12 Years a Slave and Gravity expected to give American Hustle's A-list cast a run for their money when the Oscars roll around on 2 March.
Newcomer Lupita Nyong'o, who plays an abused plantation worker in 12 Years a Slave, was given the best supporting actress award by SAG voters.
The Kenyan actress also thanked her director, British film-maker Steve McQueen, "for taking a flashlight and shining it underneath the floorboards of this nation and reminding us what it is we stand on".
She also recounted the story of phoning her father to tell him she had got the part.
"'Daddy, do you know who Brad Pitt is? I'm going to be in a movie with him!"' she recalled.
"And he said, 'I don't know him personally but I'm glad you got a job.'"
Both best actor and best supporting actor went to the stars of Dallas Buyers Club, a small film that cost just $4m (£2.4m) to make.
It is based on the true story of a homophobic Texan who gets Aids and smuggles unapproved anti-HIV drugs into the US in the 1980s.
Matthew McConaughey, in the lead role, and Jared Leto, as a transgender woman with Aids, both endured dramatic weight loss to play their parts.
McConaughey said of his SAG honour: "It really shines a great light on this bull ride we call acting.
"I've been able to recently find some characters that I can humble myself to their humanities and get feverishly drunk on their obsessions."
Warming to his theme, the 44-year-old started musing on the "magic place" that actors reach when "you're seeing the character from the inside out".
"That doesn't always happen but, boy, when it does, it feels like they can put a blindfold on you and put you in a spaceship and take you to Neptune," he added.
Cate Blanchett took home the best actress prize for her complex, cracked portrayal of a socialite fallen on hard times in Woody Allen's Blue Jasmine.
It was her 17th best actress prize of the awards season - and she is considered a near-certainty for the trophy at both the Baftas and Oscars.
But when her acceptance speech was cut short, the actress protested: "29 seconds? Matthew McConaughey spoke about Neptune!''
The SAG Awards also recognise actors working in TV, with sitcom Modern Family winning best ensemble in a comedy series and best male actor in a comedy series for Ty Burrell's dumb-but-loveable patriarch Phil Dunphy.
In his speech, Burrell outlined his steps for becoming a successful actor, which included: "Be born into a family that never had an actor in it; Use that false sense of confidence to woo and attract a spouse who's better than you; Have no skill other than being a needy extrovert; Use that lack of skill to stumble into a job."
Accepting the show's cast award - its fourth in a row - Colombian star Sofia Vergara said the honour was "mind-blowing", adding: "I can barely speak English."
Breaking Bad, which left TV screens last year, continued its victory lap around the awards shows, winning outstanding dramatic cast and for best lead actor Bryan Cranston, for his indelible performance as teacher-turned-meth dealer, Walter White.
Looking out at his former cast-mates, Cranston remarked: "We have the nicest bunch of white supremacist Nazis I have ever worked with.
"I swear to you I would kill you all over again."
British Dame Maggie Smith and Dame Helen Mirren won best actress awards for Downton Abbey and the TV movie Phil Spector respectively.
Dame Maggie was not present to accept her award, whereas Dame Helen lingered on stage, examining the trophy she'd just received.
"I love this little guy," she said. "He's so sexy, isn't he? Sort of naked but not quite..."
Michael Douglas picked up a best actor prize in the TV category for his performance as Liberace in the movie Behind The Candelabra, which was only shown on cable channel HBO in the States.
The lifetime achievement award was given to Rita Moreno, the 81-year-old actress who played Anita del Carmen in West Side Story, alongside roles in Singin' in the Rain and The King and I, and on Broadway in The Ritz and The Odd Couple.
Introduced by Morgan Freeman, the Puerto Rican star danced her way up to the podium and, upon receiving a standing ovation, let out an unscripted expletive.
"I am sorry about that word.... Actually, I am not," she said.
The star thanked the guild for honouring her "early in the third act of my life" before serenading the audience with a few lines from This Is All I Ask.