"We are excited to welcome Christina back to her red chair and can't wait to see how she mixes things up among Adam, Blake and Pharrell, in what will be an incredibly competitive competition," Paul Telegdy, president of alternative and late night programming at NBC Entertainment, said in a statement. "These four talented artists are at the top of their game as musicians and as coaches. The mentoring is sure to be intense and the stakes will be high."
Williams joined the show during the current season, season seven, along with Stefani. Previous coaches include Usher and CeeLo Green. Green was part of the original cast, but has said his time with The Voice is over.
Season seven of The Voice is currently in Battle Rounds with mentors Alicia Keys, Stevie Nicks, Little Big Town and Gavin Rossdale. When the show goes into Knockout Rounds, Taylor Swift will be the mentor for all four teams.
Over the seven seasons, Levine's team has won twice, Shelton's three times and Usher once. Aguilera has never coached a Voice champion. In season five, a member of Aguilera's team, Jacquie Lee, came in second.
The Voice airs Mondays and Tuesdays at 8 p.m. on NBC.
(E! and NBC are both part of the NBCUniversal family.)