On Vegas night, the couples dance to some of the most iconic songs from hit Las Vegas shows; one couple will be eliminated; Julianne and Derek Hough perform a number from their upcoming tour.
The seven remaining couples perform dances that capture the spirit of diverse movie genres; stars from "Descendants 2" perform; guest judge Mandy Moore.
The judges each pair up with a couple and assign the couple a specific challenge; Cheryl Burke returns to the dance floor for a special performance; Calum Scott performs.