You'll Find Out 1940

... Kay Kyser

Boris Karloff

... Judge Spencer Mainwaring

Peter Lorre

... Professor Karl Fenninger

... Prince Saliano

... Janis Bellacrest

... Chuck Deems

... Aunt Margo Bellacrest

Bess Flowers

... Lady In Taxi

... Jurgen

... Kay Kyser's Band

... Ginny Simms

... Harry Babbitt

... Ish Kabibble

... Sully Mason

... Mary

Jeff Corey

... Mr. Corey

Louise Currie

... Marion

Louise Currie

... Member of Kay Kyser Band

... Jean

... Script Man

... Ms. Gaby Lawson

... Apartment Complainer

... Cabbie

... Mimi

... Penny

Leonard Mudie

... Real Karl Fenninger

... Servant

Frank O'Connor

... Apartment Responder

... Mother

... Jane

... French Maid

... Mac

... Joan

... Infant

... Georgia

... Director

... Screenplay

... Story

... Story

... Producer

... Editor

Edward Stevenson

... Costume Design

... Cinematography

Vernon L. Walker

... Special Effects