Kerry Washington has landed a permanent role on The Simpsons.The 45-year-old actress is set to voice the part of Rayshelle Peyton on the long-running animated sitcom, Bart Simpson's fourth-grade teacher.Kerry's alter ego is a replacement for Mrs. Krabappel, who was voiced by the late Marcia Wallace until her death in 2013.The Scandal star told Entertainment Weekly: 'She's a great teacher.