On April 12 , 2014 , Stefani made a surprise appearance at the Coachella festival , where she joined Pharrell Williams onstage during his set to perform " Hollaback Girl " . On April 29 , it was officially confirmed that Stefani would join the seventh season of '' The Voice '' as a coach , replacing Christina Aguilera . Nine years after the previous time , she attended the 2014 MTV Video Music Awards . Stefani appears as a featured artist on Maroon 5 's song " My Heart Is Open " , co-written by Sia Furler , from the band 's album '' V '' , which was performed for the first time with Adam Levine and an orchestra at the 2015 Grammy Awards . Stefani also collaborated with Calvin Harris on the track " Together " from his album '' Motion ''
2014 MTV Video Music Awards
2014 MTV Video Music Awards
Gwen Stefani