Rihanna is to join The Voice US

Last updated at 10:55
RhiannaPA

Singer Rihanna is to join The Voice US as a key adviser to all the coaches.

It's about to start it's ninth series in the US on 21 September.

Pharrell Williams performs in DenmarkReuters
Pharrell Williams performs in Denmark

Pharrell Williams, Adam Levine from Maroon 5and Blake Shelton will also return as mentors.

Gwen Stefani is returning as coach of NBC"s "The Voice" for its ninth season.AP
Gwen Stefani is returning as coach of NBC"s "The Voice" for its ninth season.

Singer Gwen Stefani will also be back - she previously served as a coach on season seven.