Boris Karloff as Dr. Friedrich Hohner

Susanna Foster as Angela Klatt

Turhan Bey as Franz Munzer

Gale Sondergaard as Luise

Thomas Gomez as Count Seebruck

June Vincent as Marcellina

George Dolenz as Amato Roselli

Ludwig Stössel as Carl Baumann

Jane Farrar as Jarmila Vadek

Ernö Verebes as Brunn

Lotte Stein as Mama Hinzl

Scotty Beckett as The King

William Edmunds as Leon, Theatre Concierge

Maxwell Hayes as Count Romburg

Dorothy Lawrence as Miss Metzger

Bella Lewitzky as Dancer (Uncredited)

Jack Richardson as Musical Conductor (Uncredited)

Polly Bailey as Cleaning Woman (Uncredited)

Stuart Holmes as King's Consul (Uncredited)

Eddie Polo as Stagehand (Uncredited)

Paul Power as Reporter (Uncredited)

Ernie Adams as Man in Audience Next to Franz (Uncredited)

Gertrude Astor as Woman in Audience Behind Franz (Uncredited)

Grace Cunard as Backstage Maid (Uncredited)

William Desmond as Backstage Technician (Uncredited)

Francis Ford as Backstage Attendant (Uncredited)

Louis Payne as Audience Member (Uncredited)

Anne Cornwall as Audience Member (Uncredited)

Rudy Bowman as Audience Member (Uncredited)

William H. O'Brien as Audience Member (Uncredited)

Helen Gibson as Audience Member (Uncredited)

Maurice Costello as Audience Member (Uncredited)

Harry Mayo as Audience Member (Uncredited)

Richard Neill as Audience Member (Uncredited)

Eric Mayne as Audience Member (Uncredited)

Barry Regan as Audience Member (Uncredited)