Christiana Figueres

Expert on Global Climate Change; Former Executive Secretary of the UN Framework Convention on Climate Change

Herschel Walker

Former NFL Running Back, 1982 Heisman Trophy Winner & Mental Health Awareness Advocate

Ken Burns

Historian & Award-Winning Documentary Filmmaker

Mitt Romney

Former Governor of Massachusetts, 2012 Republican Presidential Nominee and CEO

Stacy Brown-Philpot

Fortune 100 Board Director, Investor & Advisor; Former CEO of TaskRabbit

Sarah Silverman

Stand-Up Comedian, Actress, Singer, Producer & Writer

Julia Louis-Dreyfus

Emmy Award-Winning Actress Known For "Seinfeld" & "Veep"

John P. Kotter

Leadership & Change Management Guru

Gretchen Rubin

New York Times Best-Selling Author of "The Happiness Project;" Host of Podcast "Happier with Gretchen Rubin"

Gretchen Rubin - Knowing Yourself: Why You're Happy and You ...

Maria Bartiromo

Global Markets Editor, FOX Business Network

Willie Nelson

Country Music Singer-Songwriter Known for "On The Road Again" & "Always On My Mind"

Dr. Dean Ornish

Physician, Leading Researcher in Healthcare, Founder of the Preventive Medicine Research Institute & Bestselling Author

Alice Walker

Pulitzer Prize & National Book Award-Winning Author; Best Known for "The Color Purple"

Zain Asher

News Anchor at CNN International

David Moinina Sengeh

Minister Of Basic and Senior Secondary Education & Chief Innovation Officer for the Government of Sierra Leone

Jalen Rose

Former ESPN Analyst & NBA Player

Gwyneth Paltrow

Actress, Entrepreneur, Founder & CEO of Goop

Lawrence Summers

Professor & Former President of Harvard University; Former Secretary of the Treasury, Director of the National Economic Council, & Chief Economist of the World Bank

Jon Stewart

Talk Show Host, Comedian & Producer

Jon Stewart will return to ‘The Daily Show’ as host — just on Mondays

Andie MacDowell

Film Actress

Lynsey Addario

American Photojournalist; Contributor for National Geographic & Time Magazine

Gina Bianchini

Serial Entrepreneur, Columnist & Thought Leader; Founder of Mightybell; Co-Founder & Former CEO of Ning

Padmasree Warrior

Founder & CEO of Fable; Former U.S. CEO & CDO of NIO; Former CTO & Strategy Officer for Cisco

Dr. Henry Louis Gates, Jr.

Award-Winning Filmmaker, Literary Scholar, Journalist & Cultural Critic; Director of the Hutchins Center for African & African American Research at Harvard University

Cris Collinsworth

Former NFL Wide Receiver & Sports Emmy Award-Winning Game Analyst for NBC's "Sunday Night Football"

Pat Croce

Mega-Entrepreneur & Former NBA Team Owner

Alonzo Mourning

Naismith Memorial Basketball Hall of Fame Inductee; Co-Founder of Mourning Family Foundation

Lauren Daigle

Christian Singer-Songwriter

Jane Lynch

Emmy Award-Winning Actress, Known for "Glee" and Hosting "Hollywood Game Night"

Hannah Beachler

Academy Award-Winning Production Designer Known for Beyonce's "Lemonade" & Marvel's "Black Panther"