'The Voice' returns with the strongest vocalists from across the country invited to compete in the blockbuster vocal competition show's ninth season. Adam Levine, Blake Shelton and Pharrell Williams will return for their ninth and third seasons as coaches, respectively. Gwen Stefani will return for her second season, after a season hiatus. The advisors for this season included Missy Elliott for Team Pharrell, Brad Paisley for Team Blake, Selena Gomez for Team Gwen and John Fogerty for Team Adam. Rihanna served as an advisor for all teams during the knockouts.