as Capt. Hugh (Bullshot) Crummond
as Rosemary Fenton
as Count Otto van Bruno
as Fräulein Lenya von Bruno
as Crouch
as Prof. Rupert Fenton
as Lord Binky Brancaster
as Hawkeye McGillicuddy
as Col. Hinchcliff
as Dobbs
as Hotel Manageress
as Chairman of the Institute
as Nobby Clark
as Waiter
as Gentleman (uncredited)
as Albert Einstein