"We landed Rihanna to be the key advisor to all the coaches this fall," NBC Entertainment Chairman Robert Greenblatt told reporters Thursday, according to E! News. "This is one of music's true supervisors coming on board to influence the lives and careers of the performers."
The Voice has always attracted big stars in the music industry for the role, as previous seasons have featured Fun frontman Nate Ruess and Coldplay's Chris Martin.
Levine and Shelton have been mainstays on The Voice since it premiered back in 2011. This will be Williams' third time sitting in one of the big red chairs and Stefani's second stint. Former coach Christina Aguilera is reportedly expected to return for Season 10 and take Stefani's place again.
The Voice's ninth edition is scheduled to debut September 21 at 8PM ET/PT on NBC.