Trivia: Hitchcock's cameo appearance, a signature feature of his films, takes place near the end. He is seen outside a phone box when Jack is making a call.
Trivia: When trying to describe Bruce to a friend Grant says "He looks like, uhh, that fella in the movies, Ralph Bellamy." Bruce was in fact played by Ralph Bellamy.
Trivia: This was Charlie Chaplin's first feature film with full sound.
Trivia: This is the only Mr Wong movie, to date, where Boris Karloff did not portray the Master Detective.