Cillian Murphy has become the first Irish-born winner of the best actor award, as Oppenheimer swept the Oscars.
The film dominated proceedings, winning best picture, best director for Christopher Nolan, and best supporting actor for Robert Downey Jr.
Murphy was named best leading actor for his acclaimed portrayal of theoretical physicist J Robert Oppenheimer.
The actor said he was “overwhelmed” to have won, adding: “I’m a very proud Irishman standing here tonight.”
He thanked Nolan and producer Emma Thomas for “the wildest, most exhilarating, most creatively satisfying journey you’ve taken me on”.
Murphy also paid tribute to “every single crew and cast member, you carried me through”.
He concluded: “We made a film about the man who created the atomic bomb, and for better or for worse, we are all living in Oppenheimer’s world, so I’d like to dedicate this to the peacemakers everywhere.”
The ceremony saw Oppenheimer win seven prizes overall, while Poor Things took four – including best actress for Emma Stone – and The Zone of Interest scored two.
Downey Jr won best supporting actor for his portrayal of US government official Lewis Strauss in Oppenheimer.
Accepting the award, the actor joked: “I’d like to thank my terrible childhood, and the Academy, in that order.
“I needed this job more than it needed me,” he continued. “I stand here before you a better man because of it.”
The star also paid tribute to his wife Susan Downey, who he said had found him as a “a snarling rescue pet”, adding that she “loved me back to life, that’s why I’m here”.
Downey Jr, best known for his run as Marvel’s Iron Man, has enjoyed a hugely successful Hollywood comeback after serious drug addiction issues more than two decades ago, which saw him serve a prison sentence after missing court-ordered drug tests.
He concluded his speech by telling the audience: “What we do is meaningful and what we decide to make is important.”
