The Deep South drama The Help won three prizes at the Screen Actors Guild Awards, including best actress for Viola Davis and supporting actress for Octavia Spencer.
The Help also claimed the guild's ensemble award, the show's equivalent of a best-picture prize. Davis and Spencer won as black maids going public with uneasy truths about their white employers in 1960s Mississippi.
Jean Dujardin won the lead-actor honour for The Artist as a silent-film superstar whose career crumbles when the sound era arrives. And Christopher Plummer won for supporting actor as an elderly father who comes out as gay in Beginners. The wins boost the actors' prospects for the same honours at the February 26 Academy Awards.
Plummer would become the oldest actor ever to win an Oscar at age 82, two years older than Jessica Tandy when she won best actress for Driving Miss Daisy.
Backstage, Plummer joked about whether he would like to win an Oscar, an honour so elusive during his esteemed 60-year career that he did not even receive his first Academy Award nomination until two years ago, for The Last Station.
"No, I think it's frightfully boring," Plummer said. "That's an awful question. Listen, we don't go into this business preoccupied by awards. If we did, we wouldn't last five minutes."
On the television side, comedy series awards went to Modern Family for best ensemble; Alec Baldwin as best actor for 30 Rock; and Betty White as best actress for Hot in Cleveland.
The TV drama show winners were Jessica Lange as best actress for American Horror Story; and Steve Buscemi as best actor for Boardwalk Empire, which also won the ensemble prize.
For TV movie or miniseries, Kate Winslet won as best actress for Mildred Pierce, while Paul Giamatti was named best actor for Too Big to Fail.
Before the official ceremony, the Screen Actors Guild presented its honour for best film stunt ensemble to Harry Potter and the Deathly Hallows: Part 2. The TV stunt award went to Game of Thrones.