The concerto supposedly written by Ricardo Montalbán's young bullfighter character was "El salon Mexico" by Aaron Copland, with variations added to the piano portions for the sake of Montalbán's scenes at the piano.
Esther Williams, in her autobiography "Million Dollar Mermaid" states that during the shooting of this film, her husband at the time - Ben Gage - got drunk and had a run-in with the Mexican police, causing production to be halted as the authorities had him thrown out of the country.
Given that M-G-M's intention in making this film was to turn newcomer Ricardo Montalban into a 1940s equivalent of the silent era's great Latin Lover Rudolph Valentino, it is likely no mere coincidence that this film's basic plot, centered on bullfighting, has much in common with one of Valentino's biggest box office hits, the 1922 version of "Blood and Sand".
Although portraying their mother, Mary Astor was only almost 14 years older than Ricardo Montalbán, and 15 years older than Esther Williams.