Joaquin Phoenix won his first Oscar on Sunday for his terrifying performance as an isolated loner who becomes one of the world's best known comic book villains in "Joker."
Phoenix, 45, won the best actor Oscar after three previous nominations, crowning an awards season that has seen him sweep every major prize for his role in the standalone origin story of Batman's arch enemy.
The actor, known for playing brooding or emotionally troubled characters, dropped more than 50 pounds (22 kg) to play Arthur Fleck, an emaciated mentally ill clown who finds fame through a random act of violence in 1980s era New York City.
His Oscar win made Phoenix the second person to get an Academy Award for playing the Joker character. Heath Ledger won a posthumous best supporting actor Oscar in 2009 for playing the Joker in "The Dark Knight."
South Korean Bong Joon Ho won the best director Oscar for dark social satire "Parasite" on Sunday, becoming the first person from the Asian nation to win the award.
The film was one of the biggest winners at the Academy Awards, having already taken best international feature film and best original screenplay.
Bong, 50, beat Hollywood veterans including Martin Scorsese and Quentin Tarantino for his Korean language movie about the violent clash between haves and have-nots in contemporary Seoul.
In his acceptance remarks, Bong gave a shout-out to both directors.
"When I was in school, I studied Martin Scorsese's films. Just to be nominated was a huge honor. I never thought I would win," he said as the audience rose to its feet in applause.
"When people in the U.S. were not familiar with my film, Quentin always put my films on his list. He's here," Bong added. "Quentin, I love you!"
And then reprising a remark he made after winning, best international picture, he said: "I will drink until next morning. Thank you."