Chris Pizzello, Associated Press
Octavia Spencer arrives at the 18th Annual Screen Actors Guild Awards on Sunday Jan. 29, 2012 in Los Angeles.

LOS ANGELES — Christopher Plummer of the father-son tale "Beginners" and Octavia Spencer of the Deep South drama "The Help" have won supporting-acting honors at the Screen Actors Guild Awards, firming up their Academy Awards prospects next month.

Plummer won Sunday for his role as an elderly dad who comes out as gay after his wife's death. If he wins at the Feb. 26 Academy Awards, the 82-year-old Plummer would become the oldest actor to earn an Oscar, two years older than Jessica Tandy when she won best actress for "Driving Miss Daisy."

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