Shannon Miller

Olympic Gold Medalist, Health Advocate & Cancer Survivor

Giuliana Rancic

Entertainment Journalist & Breast Cancer Survivor

Lisa Leslie

WNBA Champion, Olympic Gold Medalist & Author of "Don't Let the Lipstick Fool You;" Coach of Ice-Cube's BIG3 Basketball League

Ali Vincent

First Female Winner of "The Biggest Loser"

Jennifer Siebel Newsom

First Lady of California; Actress & Filmmaker of "Miss Representation" and "The Mask You Live In"

Joe Theismann

World Champion Quarterback, Broadcaster & Entrepreneur

Amy Purdy

Former "Dancing with the Stars" Contestant & Paralympic Professional Snowboarder

Greg Louganis

4x Olympic Gold Medal Diver; LGBTQ Activist & Author

Joan Lunden

Award-Winning Journalist, Best-Selling Author, Health & Wellness Advocate

Daphne Oz

Emmy Award-winning Television Host, New York Times Bestselling Author, Chef & Entrepreneur

Vince Papale

Former NFL Player & Inspiration for the Movie "Invincible"

Mark Ballas

Dancing with the Stars Champion & Mental Health Activist

Dr. Travis Stork

Bestselling Author, Emergency Medicine Physician & TV Personality Known for "The Doctors"

Dr. Holly G. Atkinson

Award-Winning Medical Journalist

Dara Torres

12x Olympic Medalist, NYT Bestselling Author, Entrepreneur & Healthcare Reform Advocate

Michael Strahan

Co-Host of "Good Morning America", "Fox NFL Sunday" Analyst, NFL Hall of Famer & Super Bowl Champion

Michael Strahan and his daughter Isabella, 19, reveal her brain cancer diagnosis in emo...

Dolvett Quince

Fitness Guru & Trainer from "The Biggest Loser"

Olivia Ward

Winner of "Biggest Loser" Season 11

Dr. Michael Roizen

Chief Wellness Officer at the Cleveland Clinic & Co-Founder of RealAge; Anesthesiologist & Former FDA Advisory Committee Chair

Nik Wallenda

Acrobat, Aerialist, Daredevil & High Wire Artist