Dreamgirls (2006) : It's All Over + And I Am Telling You I'm Not Going

With the aid of new songs and a more glamorous image, Curtis and C.C. transform The Dreams into a top selling mainstream pop act by 1965. However, Effie begins acting out, particularly when Curtis' affections turn towards Deena. Curtis eventually drops Effie from the group, hiring his secretary, Michelle, to take her place. (from Wikipedia)