Holmes Herbert
Sir Reginald

Mary Gordon
Mrs. Hudson

Harry Cording
Jack Brady (uncredited)
Harold De Becker
Peg Leg (uncredited)

Paul Fix
Mueller (uncredited)

Henry Victor
Professor Frederic Hoffner (uncredited)
John Burton
RAF Officer (uncredited)

Paul Bryar
Swiss Waiter (uncredited)

Whit Bissell
London Bobbie (uncredited)

Rudolph Anders
Braun (uncredited)