Dr. Michio Kaku

World-Renowned Futurist & Theoretical Physicist

Erin Brockovich

Consumer Advocate, Author, TV Host & Environmental Activist

Amanda Beard

Olympic Gold Medalist, Co-Founder of Beard Swim Co. & Author of New York Times Bestseller "In the Water They Can't See You Cry"

Alexandra Cousteau

Environmental Activist, Storyteller & Ocean Advocate

Danny Trejo

Actor, Author, Activist & Restaurateur; Recovery & Intervention Counselor for Troubled Youth

Ellen DeGeneres

Award-Winning Comedian, TV Host, Actress & LGBTQ Activist

Jeff Orlowski-Yang

Award-winning Filmmaker, Photographer, Entrepreneur & Climate Change Activist

Sophia Bush

Actress, Humanitarian & Author

Ed Begley Jr.

Environmental Activist & Emmy Award-Nominated Actor

Winona LaDuke

Executive Director of Honor the Earth

Tim Gunn

Fashion Icon, Former Co-Host & Mentor of "Project Runway"

Doc Hendley

Global Humanitarian, Clean Water Crusader, Top 10 CNN Hero, Sustainability Advocate

Jillian Michaels

Leading Fitness Expert, Certified Nutritionist, Renowned Life Coach & Powerful Entrepreneur

Adrian Grenier

Actor Known for HBO's "Entourage"; Environmental Activist; UN Ambassador

Laura Dern

Actress, Director, Producer & Activist

Kesha

Pop Singer Known For "Tik Tok," "Your Love Is My Drug" & "Praying"

Bill Maher

Political Satirist & Host of HBO's "Real Time"

Leland Melvin

Engineer, Former NASA Astronaut & Former NFL Wide Receiver

Doug Fine

Globe-Trotting Journalist, Award-Winning Climate Correspondent, Goat-Herder & Author

Olivia Munn

Television & Film Actress; Known for "Newsroom" & "X-Men: Apocalypse"

Olivia Munn on Jon Stewart | 2022 Mark Twain Prize