On the DVD, Taina Elg says the original cast was supposed to include Cyd Charisse as the American girl, Leslie Caron as the French girl, and Kay Kendall as the English girl. Charisse decided to do Silk Stockings (1957) instead, so Mitzi Gaynor took her part. At one point, Kendall didn't want to do the film and Elg was tested for her role. Kendall took the part after all, but then Caron withdrew. Elg was tested then for THAT character and received her first major film role.
Heard in the background between the stage performances is a snippet of "Be a Clown". Cole Porter wrote this for The Pirate (1948), and he wrote the rest of "Les Girls" songs.
The last movie Gene Kelly made for MGM under his contract. It wasn't until the documentary That's Entertainment! (1974) that he would appear in another MGM musical.
Taina Elg had just given birth to her only son Raoul when she got the role of Angèle Ducros, which originally was planned for the French Leslie Caron.