RELATED: 15 Onscreen Couples You Totally Forgot Dated in Real Life. In a 2019 interview with Vanity Fair, Phoenix explained that he became vegan when he was three years old after he and his siblings realized that the fish they had been eating had once been alive. Soon after, the whole family became vegan, and Phoenix has been passionate about it ever since. In his acceptance speech when he won the Oscar for Best Actor for Joker in 2020, he spoke out about animal rights specifically while mentioning various injustices in the world.ae0fcc31ae342fd3a1346ebb1f342fcb In a new interview with the Sunday Times (via BuzzFeed), Phoenix explained that while he hopes River will want to be vegan, he won’t “force” him to go that route. “Well, certainly I would hope that [he is vegan], but I’m not going to impose my belief on my child. I don’t think that’s right,” the actor said.  Phoenix explained that he will tell River the truth about animals and where meat and other animal-derived products come from. “I’m not going to indoctrinate him with the idea that McDonald’s have a Happy Meal because there’s nothing f****** happy about that meal,” he said. “I’m not going to tell him that it’s OK to read books about all the wonderful little farm animals, and they say ‘Oink oink oink’ and ‘Moo moo moo,’ and not tell him that that’s what a hamburger is. So I’m not going to perpetuate the lie, but I’m also not going to force him to be vegan. I’ll support him. That’s my plan.” For more celebrity news delivered right to your inbox, sign up for our daily newsletter. Mara and Phoenix welcomed River in September 2020. Two months later, they used their celebrity platform to speak about an important issue while also making headlines for talking about their baby for the first time. The couple wrote an op-ed for People about migrant children being separated from their families at the border, including 545 children whose parents were still not located. “As new parents, it’s unbearable to imagine what it would feel like to have our child taken away from us for a day, let alone years,” they wrote. “But that’s the very situation those 545 children and their parents have been living through. As Americans, it’s our responsibility to continue paying attention to the plight of these families and get answers for why they still have not been located.” Mara talked about her son in an open letter in connection with the organization Farm Sanctuary for Mother’s Day. “As a new mom, Mother’s Day has taken on a special meaning this year,” the Carol star wrote, according to People. “Raising our baby, River, has opened my heart to a whole new life filled with hope and more determination than ever to create a kinder and more sustainable world. I feel so fortunate to be able to nurture my son in all of the ways that nature intended, and I wish all mothers in the animal kingdom could experience that sacred maternal bond with their young, devoid of exploitation by humans.” RELATED: Justin Timberlake May Have Just Shared a Rare Photo of His Son.