The actress, who is an honorary director at PETA (People for Ethical Treatment of Animals), wrote an open letter to the politician in response to his decision to donate $100 million (£81 million) to the vegan industry.
"Sensuality includes being engaged in the world and caring about others' feelings, and nothing is sexier than compassion," Anderson wrote. "Your recent decision to invest another $100 million in (Canada's) mushrooming plant-based industries fits that description. Were you to drop meat and dairy from your personal diet - which I so hope you will - I would be honoured to be your mentor."
The 52-year-old also praised Trudeau for helping to create new jobs in green culture amid the coronavirus pandemic.
"Your fiscally responsible move not only creates good jobs for Canadians but also spares countless animals a terrible life and death," she added. "As COVID-19 has exposed serious health risks associated with factory farms and slaughterhouses, the world needs more sensible leaders like you, who are willing to embrace clean, compassionate, and clever food solutions."