Dr. Michio Kaku

World-Renowned Futurist & Theoretical Physicist

Erin Brockovich

Consumer Advocate, Author, TV Host & Environmental Activist

Sophia Bush

Actress, Humanitarian & Author

Adrian Grenier

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

Robert Ballard

Renowned Ocean Explorer & Scientist

Alicia Silverstone

Actress & Animal Rights Activist

Melissa Rivers

Actress, Television Host & Producer, Equestrienne, and Philanthropist; Daughter of Late Comedian Joan Rivers

Tim Gunn

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

Alexandra Cousteau

Environmental Activist, Storyteller & Ocean Advocate

Cesar Millan

Host of The Dog Whisperer; Author of Cesar's Way

Alice Waters

Executive Chef, Founder & Owner of Chez Panisse; Sustainable Agriculture Advocate

Jillian Michaels

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

David Suzuki

Environmentalist & Scientist; Co-Founder of the David Suzuki Foundation

Tamron Hall

Award-Winning Journalist; Former National News Anchor for NBC News; Host of the "Tamron Hall Show"

Watch Where They Hide

Sylvia Earle

Explorer-in-Residence at National Geographic & Oceanographer; Former Chief Scientist of the NOAA

Alyssa Milano

Actress, Author, Philanthropist & Founder of Touch by Alyssa Milano; Known for "Charmed" and "Who's the Boss"

Daryl Hannah

Actress, Best Known for "Kill Bill" & "Splash"; Environmental Activist

Kevin Nealon

Former Cast Member of 'Saturday Night Live'; Co-Star on Showtime's "Weeds"

Moby

Musician, DJ, Photographer

Alison Victoria

Interior Designer; Host of HGTV's "Kitchen Crashers"