Frank Welker was the only actor who had previously been in a Dr. Seuss project, having played some characters in The Grinch Grinches the Cat in the Hat (1982).
Zelda Williams is Robin Williams' real-life daughter, who portrays his daughter in this movie. While Eleanor Columbus, who portrayed the other daughter, was Chris Columbus' daughter.
Includes footage from numerous animated adaptations of Seuss' books.
Zelda Williams's debut.