- No Stunt Double: Calling upon his vaudevillian roots, Cary Grant insisted upon doing his own stunts, including one in which he was lifted up by a railroad-crossing gate. Ann Sheridan even got into the act, driving a 400-pound motorcycle with Grant in the sidecar for a sequence. She navigated the bike expertly, except for an unfortunate run-in with a goose; its death terribly upset the actress, but despite this Sheridan had a positive experience making the film.
- Troubled Production: Filming was beset with problems. The German winter was unbearably cold and most of the cast and crew fell ill. Ann Sheridan caught pleurisy (which developed into pneumonia), Cary Grant contracted hepatitis with jaundice, and Howard Hawks broke out in hives. Production was shut down for three months, until Grant recovered and regained around 30 pounds. As a result, production went on for eight months at a cost of $8 million.
- What Could Have Been: Ava Gardner was briefly considered for Catherine, but Howard Hawks didn't think she could handle the part.
Trivia / I Was a Male War Bride