Could Christopher Plummer supplant himself as the oldest person ever to win an Oscar? You’d think so, by the thunderous palm-smacking that met the conclusion of “Barrymore” at a recent screening in New York.

Plummer had a Broadway triumph with “Barrymore” in 1997, winning a Tony Award as a tender boy of 68 -- and long before, at 82, he snagged the Academy Award for “Beginners.” (“Where have you been all my life?”)

In May, a motion picture version of “Barrymore” will premiere in theaters in Plummer’s native Canada; U.S. audiences will see it in October.

“Barrymore,” set in 1942, follows American actor John Barrymore in the waning part of his career, on an evening he has rented an old theatre to rehearse for a backer’s audition that would raise money for a revival of his youthful Broadway turn in “Richard III.”

For the 90-minute film, recorded last year, Plummer recreated his Broadway performance for multiple HD cameras over a week at Toronto’s Elgin Theatre.

In “Barrymore,” a fallen legend is coming to terms with his life of excess. It’s a path Plummer says he might have followed were it not for the course-correction provided by a stable marriage over the last 40 years. The actor attended the “Barrymore” screening recently in Manhattan, then took part in a Q&A with film critic David Edelstein.

“We used to play a game on stage of making drinking dates while speaking our lines,” Plummer said, recalling drunken Broadway nights with pals Jason Robards, Peter O’Toole and Trevor Howard.

“Jason Robards, God love him ... we used to talk on stage through our lines and say ‘Where are you going afterward? I’m gonna start at the White Horse Tavern and work my way up.’”

Edelstein asked Plummer what it was like when he heard his name read out at the Academy Awards: “Are you thinking, ‘It’s gonna be Jonah Hill?’”

Said Plummer: “By the time you get to the Oscars, you’re totally exhausted, because you’ve won other awards on the way, and of course you have to say the same ‘Thank you’ speech five times to the same bloody audience. ... I tried to change it up. I always wanted to insult (co-star) Ewan McGregor, because I love him so much. So I’d say, ‘And thanks to Ewan McGregor, that scene-stealing swine from the Outer Hebrides.’ There were remarks like that, which I just varied each night.”