Mayim Bialik

Neuroscientist, Mental Health Advocate & Actress Known for "The Big Bang Theory"

Don Cheadle

Actor, Activist & Author; Known for "Iron Man 2" & "Hotel Rwanda"

Bill Nye

"The Science Guy"; Science Communicator, TV Presenter & Mechanical Engineer; Climate Change Activist

Shailene Woodley

Actress & Environmental Activist

Nash Grier

Social Media Guru, Digital Influencer & Environmental Activist

Olivia Wilde

Actress, Screenwriter, Director, Producer & Activist

Aidan Gallagher

Actor, Musician & UN Environment Goodwill Program Ambassador; Known for "The Umbrella Academy"

Aidan Gallagher On 'The Umbrella Academy' and His Music | Seventeen

Ted Danson

Award-Winning Actor, Environmental Activist & Philanthropist, Known for "Cheers" & "The Good Place"

Laura Dern

Actress, Director, Producer & Activist

Rose Marcario

Former President and CEO of Patagonia; Partner at ReGen Ventures

Jason Momoa

Actor, Producer, Environmental Activist, Known For "Aquaman" and "Game Of Thrones"

Matt Damon

Actor, Screenwriter & Producer; Co-Founder of Water.org; Expert Advocate on Global Water & Sanitation Crisis

Jessica Alba

Actress; Entrepreneur; Founder & CEO of The Honest Company

Arnold Schwarzenegger

Actor, Producer, Director, Writer; California’s 38th Governor; Host of "Celebrity Apprentice"

Thandiwe Newton

Award-Winning British Actress Best Known for her Role in Westworld

Thandie Newton Makes Great Banana Bread, But Watch This Before You Eat It

Bill Maher

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

Cate Blanchett

Academy Award-Winning Actress Known for "Elizabeth" & "The Aviator;" Ambassador for the Australian Conservation Foundation

Olivia Munn

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

Olivia Munn on Jon Stewart | 2022 Mark Twain Prize

Mark Ruffalo

Actor, Director, Producer, Screenwriter & Environmental Activist

Edward Norton

Award Winning Actor & Filmmaker