"Oh my love," the "Joker" actor told the calf, Indigo, after saving the bovines from a slaughterhouse.
After winning Best Actor for "Joker," Phoenix touched on animal rights, cancel culture and personal growth in his acceptance speech.
Bong Joon Ho's "Parasite" swept the major filmmaking awards in a history-making night.
The "Harriet" star is the only Black actor nominated in the acting categories for the 2020 Oscars.
"I would love to share this moment with someone else," the "Harriet" actor said.
"We send a very clear message to people of color that you’re not welcome here," he said as he accepted the Best Actor award in London for "Joker."
Joaquin used his acceptance speech to honor the late actor, who played the Joker in "The Dark Knight."
Bong Joon Ho's "Parasite" became the first foreign film to take home the ceremony's top prize.
The talk show host has since donated to two charities benefiting the cleft lip and palate community.
Some notable and Oscar-nominated films join the service.