Joaquin Phoenix is looking to bring his advocacy for animals to the big screen.

On Wednesday, it was announced that the actor has acquired the film rights to the 1992 non-fiction book Free the Animals: The Amazing True Story of the Animal Liberation Front in North America.

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Written by PETA President Ingrid Newkirk, the book tells the story of ‘”Valerie,’ a young police officer whose world is turned upside down when she comes face to face with a group of monkeys removed via a search and seizure warrant served by her own department on an animal testing laboratory. The book follows ‘Valerie’ as she encounters people who are willing to risk their own freedom to save animals — even if it means challenging the system by taking direct action. She joins them in living on the run from the law that she swore to uphold.”

Phoenix has also written a forward for the books new 30th anniversary reissue.

“Yes, Free the Animals is about the balaclava-wearing heroes who break windows and laws to save animals, but it’s also about everyone,” he writes. “It’s a call to us all to take action. Whether it’s wielding crowbars and bolt-cutters or picking up a pen or a protest sign, every one of us can and must fight injustice and push for animal liberation every chance we get.”

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He goes on to write about his decision to rescue a cow and her calf from a Los Angeles slaughterhouse not long after winning his Oscar for “Joker”.

“I might not be able to sneak a camera into a laboratory at Johns Hopkins University, where owls are being mutilated, or the Oregon National Primate Research Center, where monkeys are being electro-ejaculated, but I can use my voice to narrate investigators’ footage,” he explains. “I might not be able to cut holes in deep-sea fishing nets, but I can ‘drown’ in a tank of water in a PETA video to encourage people to empathize with fish. And I can’t save every cow from being milked to death, but I can save Indigo and Liberty.”

Finally, Phoenix adds, “Please join me. Ask yourself what I ask myself: ‘What can I do ‘today’ to stop human supremacism, to stop speciesism, to help animals be respected for who they are?'”