Gael Garcia Bernal

Timothy Olyphant

Bradley Trevor Greive

The Saturdays

Cyndi Lauper

Johnny Knoxville

Bill Maher

Jason Clarke

T.I.

Ryan Seacrest

Jenna Elfman

Scott Caan

Allison Williams

Emmy Rossum

Piers Morgan

Kristen Bell

Rick Springfield

Nas

Elton John

Tenacious D

Tim McGraw

Jenny McCarthy

Richard Simmons

Julianne Hough

Kathie Lee Gifford & Hoda Kotb

Stella Starsky & Quinn Cox

Justin Bartha

The cast of 'After Lately'

Quvenzhane Wallis

Jordana Brewster

Eli Roth

Kate Mara

NeNe Leakes

Jillian Michaels

Kate Walsh

Luke Bryan

Rachel Zoe

Cesar Milan

Elisabeth Moss

Olivia Wilde

Aaron Eckhart

Steve Carell

Gerard Butler

Selena Gomez & Vanessa Hudgens

Gesine Bullock-Prado

Thandie Newton

Busy Philipps

Special One-Hour Episode

Alex Guarnaschelli

Russel Brand

Kid Rock

Josh Groban

Avril Lavigne

will.i.am

Octavia Spencer

Gabby Reece

Julia Louis-Dreyfus

Paloma Faith

Nicole Richie

Katie Couric

Topher Grace

Gwyneth Paltrow

Beth Stern

Sarah Chalke

Ryan Lochte

Kat Dennings

Michael Buble

LaToya Jackson

Edie Falco

Lady Antebellum

Peter Facinelli

Zachary Quinto

Kate Bosworth

Natalie Maines

Tyrese Gibson

Zach Galifianakis

Ludacris

Mandy Ingber

The Wanted

Isla Fisher

Jack Huston

Kelly Lynch

Anne Heche

LeAnn Rimes

Amy Adams

Lauren Conrad

Bradley Trevor Greive

Mark-Paul Gosselaar

Melissa Joan Hart

Sean Hayes

Heather Locklear

George Stroumboulopoulos

Maggie Gyllenhaal

Sandra Bullock

Angie Harmon

Eve

Channing Tatum

Denise Richards

Ciara

Stephen Moyer

Jason Derulo

Patrick Wilson

Jason Biggs

Snoop Lion

Emile Hirsch

Kris Jenner

Michael B. Jordan

Rachel Bilson

Simon Cowell

Dylan Bruce

Tamar Braxton

Alexandra Daddario

Andrew Dice Clay

Lily Collins

Amber Heard

Diane Kruger

Robbie Rogers

Macklemore & Ryan Lewis

Kendrick Lamar

Bradley Trevor Greive & animals

John Legend

William H. Macy

Diana Nyad

Mark Ruffalo

Jenna Dewan-Tatum

Nelly

Jory Markiss

Brendan Schaub

Melissa Arnot

Snooki & JWoww

Julian Lennon

Casey Wilson

Kate Bosworth & Michael Polish

Kat Dennings

Tom Hiddleston

Stephen Amell

Kelly Osbourne

Elizabeth Berkley

Sam Morgante

Avril Lavigne

Tim Allen

Kerry Washington

Jeffrey Wright

Josh Gad

Sam Claflin

Pusha T

Florida Georgia Line

Mary J. Blige

Jena Malone

Mike Tyson

Baron Davis

Orlando Bloom

Casey Affleck