Steve Whitmire as Kermit the Frog / Rizzo the Rat / Beaker / Elvises (voice)

Dave Goelz as The Great Gonzo / Dr. Bunsen Honeydew / Waldorf / Zoot (voice)

Bill Barretta as Pepe the King Prawn / Bobo the Bear / Johnny Fiama / Swedish Chef / Lew Zealand / Howard Tubman / Rowlf the Dog / Elvises (voice)

Eric Jacobson as Miss Piggy / Fozzie Bear / Animal / Yoda / Elvises (voice)

David Arquette as Daniel

Joan Cusack as Rachel Bitterman

Matthew Lillard as Luc Fromage

William H. Macy as Glenn

Whoopi Goldberg as Daniel's 'Boss'

Carson Daly as Self

Kelly Ripa as Self

Joe Rogan as Self

Molly Shannon as Self

Robert Smigel as Triumph, the Insult Comic Dog (voice)

Zach Braff as Dr. John "J.D." Dorian

Sarah Chalke as Dr. Elliot Reid

Neil Flynn as Janitor

John C. McGinley as Dr. Perry Cox

Judy Reyes as Nurse Carla Espinosa

Bill Lawrence as Self

Mel Brooks as Joe Snow (voice)

Dave 'Squatch' Ward as Sally Ann Santa Claus

Brian Henson as Scooter / Janice / Sal Minella (voice)

Kevin Clash as Sam Eagle (voice)

John Henson as Sweetums (voice)

Jerry Nelson as Robin the Frog / Statler / Announcer / Pops / Floyd Pepper

John E. Kennedy as Dr. Teeth (voice)

Allan Trautman as Eugene the Tuba Player (voice)

Alice Dinnean as Additional Muppet Performer (voice)

Geoff Redknap as Additional Muppet Performer (voice)/ Sweetums

Denise Cheshire as Additional Muppet Performer (voice)

Drew Massey as Additional Muppet Performer (voice)

Adam Behr as Additional Muppet Performer (voice)

Gord Robertson as Additional Muppet Performer (voice)

Dawn Lewis as Fear Factor Contestant

Colin Foo as Security Guard

Marci Dacus as Fear Factor Contestant (uncredited)

Yee Jee Tso as Angel 1

Dan Joffre as Angel 2

Jonathan Bruce as Fat Angel

Cameron McDonald as Safari Animal Tracker

Darrell Lee-Izeard as Thin Angel

Chantal Strand as Nancy Nut-What

Robin Mossley as Nicki Nut-What

Dan Payne as Handsome Executive

Julia Arkos as Sally Ann Representative