US actor Joaquin Phoenix accepts the award for Best Actor in a Leading Role for "Joker" onstage during the 92nd Oscars at the Dolby Theatre in Hollywood, California on Feb 9, 2020. (MARK RALSTON / AFP)

LOS ANGELES - 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, and invoked his late brother River Phoenix in one of the most emotional acceptance speeches of the night.

South Korean social satire Parasite won the Oscar for best picture on Sunday, making history as the first film not in the English language to win the movie industry’s highest honor.

Joaquin Phoenix, 45, won the best actor Oscar after three previous nominations

Brad Pitt and Laura Dern won their first acting Oscars on Sunday.

Dern took home the Oscar for best supporting actress for her role as a ruthless divorce lawyer in Marriage Story, and dedicated it to her celebrity parents Diane Ladd and Bruce Dern.

Pitt was named best supporting actor for playing a charming stunt double in Once Upon a Time in Hollywood after having collected an armful of trophies earlier this year for the role. It was his first acting Oscar.

Renee Zellweger won the best actress Oscar for her performance as an ageing Judy Garland in the musical biopic Judy.

World War One movie 1917 won three Oscars, for its stunning “one-shot” feel cinematography, for visual effects and for sound editing.

Netflix movie The Irishman a costly Mafia saga directed by Martin Scorsese that had 10 Oscar nominations, came away empty- handed.

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 archenemy.

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US actress Laura Dern poses with the award for Best Actress in a Supporting Role for "Marriage Story" in the press room during the 92nd Oscars at the Dolby Theater in Hollywood, California, Feb 9, 2020. (FREDERIC J BROWN / AFP)

“I’ve been a scoundrel in my life, I’ve been selfish, I’ve been cruel at times, I’ve been hard to work with. I’m grateful so many of you in this room have given me a second chance,” Phoenix said in accepting his award.

“When he was 17, my brother wrote this lyric, he said: Run to the rescue with love and peace will follow,” he said in concluding his speech tearfully to a standing ovation.

River Phoenix died of a drug overdose at a Hollywood night club in 1993 at age 23.

The actor, known for playing brooding or emotionally troubled characters, dropped more than 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.

Dark and unsettling, Phoenix’s Joker is far removed from the comic book characters traditionally seen on screen. Matthew Belloni, editorial director of the Hollywood Reporter, described it last year as “among the most chilling characters I have ever seen in film.”

Publicity averse and intense, Phoenix has a reputation for completely inhabiting characters that have ranged from country singer Johnny Cash in Walk the Line, to Jesus Christ in Mary Magdalene and an impressionable drifter who enters a cult in The Master.

US actor Brad Pitt accepts the award for Best Actor in a Supporting Role for "Once upon a Time...in Hollywood" during the 92nd Oscars at the Dolby Theatre in Hollywood, California on Feb 9, 2020. (MARK RALSTON / AFP)

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In 2010, he almost succeeded in fooling the world that he had given up acting to try to become a rapper in the fake documentary I’m Still Here.

A strict vegan and advocate for the environment, Phoenix was born to missionary parents who traveled through Central and South America before settling in Los Angeles, where he became a child actor.