Christopher Plummer of the father-son tale “Beginners” and Octavia Spencer of the Deep South drama “The Help” won supporting-acting honours at Sunday’s Screen Actors Guild Awards, firming up their Academy Awards prospects next month.

Plummer, who won for his role as an elderly dad who comes out as gay after his wife’s death, 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.”

“I just can’t tell you what fun I’ve had being a member of the world’s second oldest profession,” Plummer said.

Spencer, a veteran actress who had toiled in small TV and movie parts previously, had a breakout role in “The Help” as a brassy maid joining other black housekeepers to reveal uneasy truths about their white employers in 1960s Mississippi.

“I’m going to dedicate this to the downtrodden, the under-served, the underprivileged, overtaxed whether emotionally, physically or financially,” Spencer said.

On the television side, Alec Baldwin won best actor for a comedy show for “30 Rock,” and Betty White won for best actress in a comedy series for “Hot in Cleveland.”

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.”

Nominees for the lead-acting honours, which were to come toward the end of the ceremony, include Globe winners George Clooney for the family drama “The Descendants,” Meryl Streep for the Margaret Thatcher tale “The Iron Lady,” Michelle Williams for the Marilyn Monroe story “My Week with Marilyn” and Jean Dujardin for the silent film “The Artist.”

Spencer’s “The Help” co-star Viola Davis also is in the running, along with Leonardo DiCaprio for the J. Edgar Hoover biography “J. Edgar,” Brad Pitt for the baseball story “Moneyball” and Glenn Close for the Irish drama “Albert Nobbs.”

The winners at the SAG ceremony typically go on to earn Oscars. All four acting recipients at SAG last year later took home Oscars Colin Firth for “The King’s Speech,” Natalie Portman for “Black Swan” and Christian Bale and Melissa Leo for “The Fighter.”

The same generally holds true for the weekend’s other big Hollywood honors, the Directors Guild of America Awards, where Michel Hazanavicius won the feature-film prize Saturday for “The Artist.” The Directors Guild winner has gone on to earn the best-director Oscar 57 times in the 63-year history of the union’s awards show.

SAG also presents an award for overall cast performance, a prize that’s loosely considered the ceremony’s equivalent of a best-picture honour. However, the cast award has a spotty record at predicting what will win best picture at the Oscars.

While “The King’s Speech” won both honours a year ago, the SAG cast recipient has gone on to claim the top Oscar only eight times in the 16 years since the guild added the category.

Airing live on TNT and TBS from the Shrine Exhibition Centre in downtown Los Angeles, the show features nine television categories, as well.

Receiving the guild’s life-achievement award is Mary Tyler Moore. The prize was to be presented by Dick Van Dyke, her co-star on the 1960s sit-com “The Dick Van Dyke Show.”