`` The Voice '' coaches Gwen Stefani and Blake Shelton . Blake Shelton and Gwen Stefani both lip-sync for Gwen Stefani . ` `` The Tonight Show Starring Jimmy Fallon '' coaches team up for a `` duet '' Lip-sync battles are popular feature of ` The Voice ''
Blake Shelton and Gwen Stefani both lip-sync for Gwen Stefani . ` `` The Tonight Show Starring Jimmy Fallon '' coaches team up for a `` duet '' Lip-sync battles are popular feature of ` The Voice ''