Joaquin Phoenix used his acceptance speech at the Oscars to slam the diary industry and champion a string of progressive causes.
The 45-year-old won Best Actor at the Academy Awards for his portrayal of a mentally ill loner in supervillain origins story Joker.
His win had been long-expected and few will have been surprised to hear Olivia Colman read out his name.
There was hardly a flicker of emotion on Phoenix's face when he was called and he retained a sombre air as he took to the stage.
During his speech, he rallied against injustice - listing gender, race, sexuality and animal and indigenous rights as being of particular importance.
"I think that we've become very disconnected from the natural world," Phoenix, who is a vegan, said.
"And many of us, what we're guilty of is an egocentric worldview, the belief that we're the centre of the universe. We go into the natural world and we plunder it for its resources.
"We feel entitled to artificially inseminate a cow and when she gives birth, we steal her baby, even though her cries of anguish are unmistakable. And then we take her milk that's intended for her calf and we put it in our coffee and our cereal."
Phoenix admitted to having been a "scoundrel" in his life, saying he was "selfish... cruel" and hard to work with, and thanked the audience for giving him a second chance.
He added: "And I think that's when we're at our best, when we support each other, not when we cancel each other out for past mistakes, but when we help each other to grow, when we educate each other, when we guide each other toward redemption."
Phoenix ended his speech by quoting his late brother, the actor River Phoenix, saying: "When he was 17, my brother wrote this lyric, he said: run to the rescue with love and peace will follow. Thank you."
Earlier, Phoenix paid tribute to his fellow nominees - Leonardo DiCaprio, Adam Driver, Antonio Banderas and Jonathan Pryce - saying they "share the same love, the love of film" and acting had given him "the most extraordinary life".
Phoenix, who was nominated for four Oscars, said the greatest gift his profession had given him was "the opportunity to use our voice for the voiceless".
Following the trend from his acceptance speeches throughout awards season, he struck a serious tone and said he had been thinking about the "distressing issues that we face collectively".
Phoenix persuaded the Golden Globes to go meat-free and attended a protest hours before the Baftas demanding animal equality.
Also among the winners at the 92nd Academy Awards was Bong Joon-ho, who took home Best Director for his film Parasite, which also became the first non-English language film to walk away with the award for Best Picture.
