Kieran Culkin shocked the audience at the Dolby Theatre in Los Angeles with a swear-laden speech while accepting the Academy Award for Best Supporting Actor.
The Succession star, 42, won the award for his role in Jesse Eisenberg’s drama A Real Pain, which follows two American cousins who embark on a tour of Auschwitz.
He beat out fellow nominees Guy Pearce (The Brutalist), Yuriy Borisov (Anora), Edward Norton (A Complete Unknown) and Culkin’s Succession co-star Jeremy Strong, who was nominated for playing Roy Cohn in the Donald Trump biopic The Apprentice.
After being presented the award by Robert Downey Jr, Culkin remarked: “Oh my God that’s crazy. I don’t even know, thanks for handing this to me. This means a lot coming from you.
“He's right, by the way, Jeremy, you're amazing in The Apprentice. I love your work, it's f***ing – I'm not supposed to single anyone out here, but you were great, and I've already lost whatever speech I prepared.”
The swearing, which included another expletive when Culkin realised his error, was bleeped out on the ceremony’s US broadcast, but made it to ITV’s live coverage uncensored.
In his speech, Culkin also paid tribute to his wife, British advertising specialist Jazz Charton.

He recalled the aftermath of the Emmys last year, when he joked on stage that Charton had promised him another child if he won the award.
“After the show, we’re walking through a parking lot … and she goes, ‘Oh, God, I did say that!'” Culkin said. “‘I guess I owe you a third kid.’ And I turned to her, and I said, ‘Really, I want four.’ And she turned to me – I swear to God, this happened there’s just over a year ago – she said, ‘I will give you four when you win an Oscar.'”
“No pressure,” he added, looking at his wife in the crowd, “but let’s get cracking on those kids.”
Culkin had been the favourite to win Best Supporting Actor at the Oscars, having dominated the category in most of the other competitions this awards season.