Rihanna has officially been added as a part of the cast of season 9 of The Voice, signing on as a key advisor to the show’s four coaches Adam Levine, Blake Shelton, Pharrell and Gwen Stefani. NBC exec Bob Greenblatt made the announcement this morning at the Television Critics’ Assn. press tour in Beverly Hills. Past key advisors have included Coldplay’s Chris Martin, Fun’s Nate Ruess and Taylor Swift. Will you be tuning in when it premieres on September 21?