After a storied 60-year career on stage and screen, Christopher Plummer became the oldest-ever Oscar winner on Sunday night, claiming the best supporting actor prize for his poignant turn as an elderly widower who embraces his homosexuality in “Beginners.”

It’s the first Academy Award for Plummer.

“You’re only two years older than me darling, where have you been all my life?” said Plummer, 82, as he regarded the golden statuette at the 84th edition of the awards.

“I have a confession to make. When I first emerged from my mother’s womb, I was already rehearsing my Academy thank-you speech. But it was so long ago, mercifully for you I’ve forgotten it. But I haven’t forgotten who to thank.”

He went on to express gratitude to his fellow nominees, “Beginners” director Mike Mills, co-star Ewan McGregor, his daughter Amanda Plummer and his wife of 43 years, Elaine Taylor.

The previous oldest Oscar winner was Jessica Tandy who was 80 when she won for “Driving Miss Daisy.”

Plummer beat out Kenneth Branagh, Jonah Hill, Nick Nolte and fellow octogenarian Max von Sydow. He took the stage to a standing ovation from acting luminaries including Brad Pitt and Meryl Streep.

Sunday’s victory is the culmination of a remarkable career for the Toronto-born, Montreal-raised Plummer, widely regarded as one of the finest actors of his generation.

Movie-goers likely know him best as Capt. Georg Von Trapp in 1965′s “The Sound of Music,” but Plummer had mixed feelings about that sugary smash. The role is but one of some 200 astoundingly diverse credits he has amassed both on the big and small screen.

In the ’70s, his films included “The Return of the Pink Panther” and “The Man Who Would Be King,” while the ’80s included a role in the TV miniseries “The Thorn Birds” and the ’90s saw him play a Klingon in “Star Trek VI: The Undiscovered Country.”

Amid the steady screen work, Plummer continued to work onstage, frequently returning to Ontario’s Stratford Shakespeare Festival to take on some of theatre’s greatest roles including Hamlet, Lear and Prospero.

Many critics thought Oscar would come calling after Plummer’s eerie rendering of newsman Mike Wallace in 1999′s “The Insider,” but he was overlooked.

In the past decade, the indefatigable actor seemed to take on more film roles than ever, appearing in “Syriana,” “The Imaginarium of Doctor Parnassus” and doing voicework as explorer Charles Muntz in the Pixar hit “Up.”

Finally, two years ago, Plummer was rewarded with his first Academy Award nomination for playing Russian writer Leo Tolstoy in “The Last Station.”

At the time, he affably noted that Charlie Chaplin had to wait until he was in his 80s to receive an Oscar.

Earlier in Sunday’s broadcast, host Billy Crystal joked about Plummer’s advanced age cracking: “He may be walking up on stage tonight. Because apparently he wanders off.”

Plummer has called “Beginners” one of his most enjoyable movie roles yet.

Based on Mills’ own experience with his father, the film shows an impish, playful side of the actor.

He plays Hal, a retired museum director who comes out of the closet after the death of his wife of 45 years. As his somewhat baffled son (McGregor) looks on, Hal embraces his newfound social sphere with child-like wonder, taking a much-younger lover (Goran Visnjic of “ER” fame) and discovering the joys of house music while sporting a jaunty bandanna. His fresh start is abruptly upended when he learns he has cancer.

During his awards season run, Plummer has repeatedly praised Mills and says he’s long admired the work of McGregor.

The role has already earned him a Golden Globe, a Screen Actors Guild Award and a BAFTA (Britain’s version of the Oscars) and he was considered a virtual lock for the Oscar.

The veteran actor has also been burning up the screen in another Oscar contender: “The Girl With the Dragon Tattoo.” He’s due to return to Stratford this summer to debut a one-man show entitled “A Word or Two.”