Did You Know?

Louis Barron and Bebe Barron worked on the electronic soundtrack music "tonalities" for only three months, the length of time given them by Dore Schary, head of MGM. He authorized the studio to send them a complete workprint at Christmas 1955. They received the complete 35mm Eastmancolor workprint at New Year's 1956, a week later, still with many visual effects sequences missing and timed in with blank leader by editor Ferris Webster. From January 1, 1956 to April 1, 1956, they worked on the soundtrack score in their Greenwich Village studio in New York City while the film was in post-production in Culver City. The score was completed and delivered to MGM on April 1, 1956, and the film was released for a studio sneak preview soon afterward. The musician's union, however, objected to the soundtrack, and blocked the Barrons from being credited as "composers", hence the term "electronic tonalities".

David Rose, composer of light orchestral music such as "Holiday For Strings", was originally hired to write the score. He was relieved of his contract by producer Dore Schary in December 1955 when Schary discovered avant-garde electronic music creators Louis and Bebe Barron in a nightclub in Greenwich Village, New York, and hired them on the spot. The only confirmed piece of music which still remains from Rose's discarded original score is his Main Title Theme, which he released as a single on MGM Records in 1956.

The model of the "flying saucer" style Earth space cruiser was retained by the MGM prop department and subsequently used in a number of productions on the MGM lot, including the "To Serve Man" of the Twilight Zone. Robby the Robot, his ground transporter, and crew uniforms would be used on that show as well.

In preparing this film for production, MGM borrowed a print of This Island Earth from Universal-International.

This movie was filmed on the same sound-stage on which the movie The Wizard of Oz had been filmed seventeen years earlier; the set of Altaira's garden is a reuse of the Munchkin Village set from The Wizard of Oz.

Robert Kinoshita, who is credited as building Robby the Robot, was also Art Director for the TV series Lost in Space. Many of the Lost in Space Robot's features are similar to Robby's: glass "head" with animated elements; rotating antenna "ears" (although LiS Robot's ears rarely moved after the pilot episode); flashing light "mouth"; chest panel with more animated elements. For that matter, much of the layout of Forbidden Planet's spaceship is mirrored by LiS's Jupiter 2: saucer shape; integral landing gear/entry stairs; lower external dome with animated lights; central, plexi-domed navigation station; vertical hibernacula arranged along perimeter. In addition, Robby and the LiS Robot had a couple of "family reunions" in two LiS episodes: Lost in Space: War of the Robots and Lost in Space: Condemned of Space.

The planet on which Edward and Altaira Morbius live is Altair IV, which according to Star Trek: Deep Space Nine is also a Federation planet. Director Fred M. Wilcox consulted with scientists before making the decision that the planet's sky would be green.

The scene in which the image of Altaira appears in the Krell's "plastic educator" device was achieved with several special effects, including superimposed film footage of the charge from an electrical generator, hand-drawn animation, and a traveling matte cut from film footage of Anne Francis.

Robby the Robot currently resides in the private collection of director William Malone

The movie's poster was as #5 of "The 25 Best Movie Posters Ever" by Premiere.

MGM had had a full animation department at one time but by 1956 it was largely dismantled. Critical animation effects (landing beam, weapons, Robby overloading, the Id Monster) were provided by Joshua Meador on loan to MGM from Disney. Meador's recognizable style can be readily discerned from that of the other three effects animators working on Alice in Wonderland and in other Disney releases.

Star Trek creator Gene Roddenberry has been quoted as saying that this film was a major inspiration for the series. Perhaps not accidentally, Warren Stevens, who plays "Doc" here, would later be a guest star in 1968's Star Trek: By Any Other Name, where the true shape of the alien Kelvans, like the Krell in this movie, was implied to be extremely non-humanoid but never shown.

Studio chief Dore Schary and producer Nicholas Nayfack were unsure about releasing the film with a solely electronic score by Louis Barron and Bebe Barron. A rough cut of the film was previewed with the electronic score. The audience reaction to the film overall was so favorable that Dore Schary ordered the rough cut to be released with the electronic score and no further editing.

The only sound film produced without any musical score or theme music, only the "electronic tonalities" by Louis and Bebe Barron.

This film marked one of the first times a science fiction project had received a large budget. The genre had rarely been taken seriously by studio executives, and had generally received the most meager of budgets. The critical success of this film convinced many in the film industry that well-funded science fiction projects could be successful. Film historian Ben Mankiewicz has claimed that Forbidden Planet's success made future big-budget science fiction films possible.

The character of Altaira Morbius spends the majority of the movie barefoot. She only wears shoes when visiting the site of the C57D landing and at the end as she prepares to leave Altair IV.