Hamilton, who also uses his platform to speak out about animal agriculture, praised the Joker actor on Instagram to his 14.2 million followers.
'Proud and grateful'
"Joaquin Phoenix has led the way for the world here and set such an incredible example," Hamilton wrote. "I am so proud and grateful to know there are people like him, with all the success and fame to use his voice for the greater good.
"I aspire to be able to do this. One of my biggest fears is speaking in front of the world on a stage like this, not finding the right words to express my thoughts.
"But I'm going to overcome it someway somehow and the only way I guess is to confront the fear and put the work in. Then I can project my heart's desire and use my voice to help heal the world."
'Fight against injustice'
Phoenix scooped the Academy Award for Best Actor at this year's Oscars, and used his speech to speak about cancel culture, the dairy industry, and gave an emotional tribute to his brother Rive who died in 1993.
"I think at times we feel or are made to feel that we champion different causes," the acclaimed actor said. "But for me, I see commonality. I think, whether we’re talking about gender inequality or racism or queer rights or indigenous rights or animal rights, we’re talking about the fight against injustice.
"We’re talking about the fight against the belief that one nation, one people, one race, one gender, one species, has the right to dominate, use and control another with impunity.
"I think we’ve become very disconnected from the natural world. Many of us are guilty of an egocentric world view, and we believe that we’re the center 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 steal her baby, even though her cries of anguish are unmistakable. Then we take her milk that’s intended for her calf and we put it in our coffee and our cereal.
"We fear the idea of personal change, because we think we need to sacrifice something; to give something up. But human beings at our best are so creative and inventive, and we can create, develop and implement systems of change that are beneficial to all sentient beings and the environment."