Stefani, who joined the series with Pharrell in Season 7, was absent last season when long-time judge Christina Aguilera returned.
"I'm coming back and am so excited!" she said in a statement. "It's so inspiring to be around such incredible talent and music. I'm looking forward to working again with Adam, Blake and Pharrell. I love those guys." Added Shelton: "Adam, Gwen, Pharrell and I had a blast together in Season 7 and I'm excited we're back together again. They are all so talented but I'm pretty damn excited about another winning season for Team Blake."
Carson Daly returns to host the show, which will be back in September.