Amber Riley, who has been preparing for this role ever since the first season of Glee, will soon play Effie White in Dreamgirls. Riley, who recently appeared as Addaperle in The Wiz Live!, will take the stage at the Savoy Theatre in the 1981 musical’s November revival. White, an analogue for Florence Ballard, the ousted original member of the Supremes, gets the iconic torch song “And I’m Telling You I’m Not Going,†which definitely helped Jennifer Hudson earn her Oscar when she played the role in 2006’s film adaptation. Glee took full advantage of Riley’s pipes — and the fact that her character was constantly passed over for the more conventional star Rachel Berry — to have her sing several of Effie’s songs on the show. So you might say Riley’s pretty well prepared.