Mickey Rooney had to film all of his scenes in one month before he had to report for basic training to serve in World War II.
Dame Elizabeth Taylor fell in love with King Charles while visiting the Rivera Country Club. He was acquired by MGM for $800 to appear in this movie with her. Taylor spent time each day riding, caring, and bonding with him in order to prepare for her role in this movie. King Charles was reported to be aggressive to his handlers except for Taylor. She and King had a special bond that was evident throughout the movie. At the end of the movie, Taylor found out that she had been gifted "The Pie", and she and King Charles remained together until his death.
Dame Elizabeth Taylor fell from the horse and broke her back during the filming of the racing scene. Although she recovered quickly, she suffered greatly later in life.
After production was completed, arrangements were made to allow Dame Elizabeth Taylor to keep the horse. She kept the horse from age 13 until it died when she was 24.
Despite this movie's locale, no attempt was made by the cast to employ English accents. In fact, Anne Revere's Academy Award-winning performance as wise and unflappable Mrs. Brown was so entrancing that neither audiences nor critics pointed out that it was rendered with a pronounced New York accent.