Filmed August 8-October 11 1940, the 7th of 8 features to star Boris Karloff and Bela Lugosi, and the only time that fellow Hungarians Lugosi and Peter Lorre ever shared the screen.
Many props and miniatures from King Kong (1933) appear in this fellow RKO production. In a secret chamber are the Willis O'Brien models of the Triceratops, a spider from the famous deleted crevasse scene as well as other creatures and island native props.
Jimmy McHugh and Johnny Mercer supplied another song, "Don't Think This Ain't Been Charming" that did not make the final cut.
At the time this was made, Kay Kyser and his band had a very popular radio show as "Kay Kyser and his Kollege of Musical Knowledge."
The call letters on the radio push buttons in the opening credits are of actual stations (e.g., KFI, WMAQ, WRC, WLW, etc.).