Pal said he had the idea to make a film out of "tom thumb" in the late 1940s when making Puppetoons for Paramount. In June 1947 he announced he would make the movie as his first feature, using a combination of actors, animation and animals. He signed a deal with United Artists to make the movie for a reported $2 million with Woody Herman and Peggy Lee to star. Buddy Kaye and Sam Kiberg signed to make songs. In November Pal was reported as filming Sierra backgrounds. In January 1948 Pal said Buster Keaton and Thomas Mitchell would appear in the film.