Trivia: Steven Spielberg saw this film when he was a child and was fascinated by the Martians. He later based E.T. from E.T. the Extra-Terrestrial (1982) on them.
Trivia: In the scene were Blondie is using the radio, the message he is intercepting is about the Battle of the Bulge.
Trivia: When Gregory Peck puts his hand into the Mouth of Truth and withdraws it (hand tucked into sleeve) the scream that Audrey gives is real. The prank was unscripted, but the reaction so perfect that it was left in.
Trivia: According to the bonus material on the DVD, the monster was used as an after thought. The director and writer thought the audience's imagination would suffice, but the higher-ups at Universal felt otherwise.
Trivia: Even though the film was made in 3-D, director Andre de Toth could not see the effect as he was blind in one eye.
Trivia: The only Tom and Jerry cartoon in which Edward Plumb provided the music score.
Trivia: When a group of people are watching a TV towards the end of the cartoon, there is a banner above the set saying "Foster's Television" - a reference to the Warner Brothers story writer Warren Foster.
Trivia: When Waldo and Loco (Betty Grable) are at the lodge, Loco says the music playing on the radio is Harry James. Waldo asks how she knows that, and she says she just knows that it's him. This is a movie in-joke because at that time, Grable was married to Harry James, the famous bandleader, in real life.
Trivia: The film was given an "X" certificate in Britain, although it was later played on children's television.
Trivia: Towards the end of the race, they stop outside a pub, which has ten minutes before it opens. This pub is on the corner of the High Street and Station Approach in West Drayton, and would not be on the journey between Brighton and Westminster Bridge, London. It was likely used as it is fairly close to Pinewood Studios, approx. 5 miles away. (01:11:41 - 01:16:18)
Trivia: Anne Crawford plays Morgan Le Fey, the mother of Modred (Stanley Baker). In real life, Crawford was only eight years older than Baker.
Trivia: At the end of the movie, there is a double wedding at sea with the ship's captain officiating. Most people assume that a ship's captain automatically has that authority. However, in order to officiate at a wedding at sea, the captain also must be a minister, a judge or justice of the peace, or a Notary Public.
Trivia: Look at the flag on the tail of the bizarre animal which the animator re-draws Daffy as - it reads "screwball."