It will premier on August 13.
Toei has uploaded a new trailer for the Aikatsu Stars! Film which reveals the history.
Anime News Network describes the Movie historya s follows:
“The film’s plot is set in a southern island, where a Legendary Dress Audition is taking place. Nijino and the others must find secret dresses said to be hidden somewhere in the island. The “Aikatsu! ~Nerawareta Mahō no Aikatsu! Card~” short has the protagonists starring in a movie directed by Ichigo Hoshimiya, and they must find a way to acquire the magical Aikatsu card that can grant any wish.”
Besides the movie, an animated short will be with it called: “Aikatsu! -Aiming For the Magic Aikatsu Card-”
Via: Anime News Network