Britney Spears

Steve Augeri of Journey

Stephen Pearcy of Ratt

Regis Philbin

Amare Stoudamire

Adam Shankman

Malin Akerman

Zac Efron

Tim Robbins

Miley Cyrus

Vince Vaughn

Hugh Jackman and Constantine Maroulis

Alex Rodriguez

Cameron Diaz

Julianne Hough and Ryan Seacrest

Steven Tyler and Randy Jackson

Steven Tyler and Constantine Maroulis

Tom Cruise and Constantine Maroulis

Kevin Cronin of REO Speedwagon

Tommy Shaw of Styx

Mick Jones

Poison

Johnny Damon

Amanda Seyfried and Dominic Cooper

Jane Krakowski

Michael Keaton

Leslie Mann

Judd Apatow

Billy Joel

Audrina Patridge

Taye Diggs

Susan Sarandon

Nickelback

Tori Amos

Tiffany

Lita Ford

Debbie Harry

Toby Maguire and Patrick Wilson

Lea Michele

Leighton Meester

John Stamos

Jamie Lynn Spears