• In the scene where Mortimer Brewster is sitting on a tombstone in the graveyard outside his Aunt's home, one of the headstones behind him reads "Archie Leach". Cary Grant's real name is Archie Leach. See also His Girl Friday (1940).
• The film went unreleased for 3 years after it was completed, waiting for the Broadway play to finish its run. On stage, Boris Karloff played Raymond Massey's character, Jonathan Brewster, who "looks like Karloff".
• Cary Grant donated his entire salary, $100,000, to the U.S. War Relief Fund.
• Bob Hope turned down the role of Mortimer Brewster.
• Mortimer's repeated phrase at the end of the film declaring the secret of his birth was originally "I'm a bastard!" However, it was demanded that it was changed to "I'm the Son of a sea cook!"

Contributions

• Holz (2008-12-09)

  Source: not available

  Peter Lorre's character is loosely based on gangland surgeon Joseph Moran.