Originally, Mickey Mouse was going to appear in the dancing sequence from Kelly's 1945 film, Anchors Aweigh. Some sources claim Walt Disney initially agreed to loan out Mickey, but Roy O. Disney rejected the deal. According to Bob Thomas's book on Roy, the studio was in debt after World War II and they were focusing on trying to get their own films out on time. According to Roy, they had no business making cartoons for other people. So at the last minute, Mickey's appearance in the film was replaced by Tom and Jerry, MGM's famous cartoon stars at that time.
Phineas acted as Kelly in a parody of Singin' in the Rain in the Phineas and Ferb episode "Rollercoaster: The Musical!," and Heinz Doofenshmirtz did the same thing in the episode, "The Great Indoors".