Poehler is a former "SNL" cast member who will return to make her hosting debut. Perry's No. 1 smash "California Gurls" has become the song of the summer.
NBC says "SNL" will welcome four new cast members this season. They include Vanessa Bayer, Paul Brittain, Taran Killam and Jay Pharoah.
Cast member Will Forte recently left the show after eight seasons and Jenny Slate left after one season.