Kermit and Fozzie are newspaper reporters sent to London to interview Lady Holiday, a wealthy fashion designer whose priceless diamond necklace is stolen. Kermit meets and falls in love with her secretary, Miss Piggy. The jewel thieves strike again, and this time frame Miss Piggy. It's up to Kermit and the rest of the Muppets to bring the real culprits to justice.

Jim Hensonas Kermit the Frog / Rowlf the Dog / Dr. Teeth / Waldorf / Swedish Chef / The Muppet Newsman / Zeke / Man in Dubonnet Club
Frank Ozas Miss Piggy / Fozzie Bear / Animal / Sam the Eagle / Gramps / Swedish Chef (voice)
Dave Goelzas The Great Gonzo / Beauregard / Zoot / Dr. Bunsen Honeydew / Lobbuck Lou / Singing Food (voice)
Jerry Nelsonas Sergeant Floyd Pepper / Pops / Lew Zealand / Louis Kazagger / Bellhop Rat / Slim Wilson / "Dirty Bird" / Man in Park
Richard Huntas Scooter / Statler / Sweetums / Janice / Beaker / Bellhop Rat / Bubba / Gramps / Monster / Singing Food / Cab Driver
Charles Grodinas Nicky Holiday
Diana Riggas Lady Holiday
John Cleeseas Neville
Robert Morleyas British Gentleman by Pond
Peter Ustinovas Truck Driver
Oswald Morris