Christina revealed the news on her Twitter account, sending out a message to her 12million followers which read: "So excited to have you join #TheVoice squad @gwenstefani! Welcome to our crazy fam! Kisses- xoxo #blondesdoitbest"
Christina Aguilera confirms Gwen Stefani for The Voice
Gwen has been rumoured to join the show for some weeks now, after Pharrell Williams was confirmed as a new judge at the end of March.
Gwen will be filling in for Shakira, who will be spending the summer touring with her new album, and then later Christina, who will be close to nine months pregnant by the time the auditions begin.
She will be joining Pharrell with returning coaches Blake Shelton and Adam Levine.
Pharrell will replace Cee Lo Green in the singing competition's upcoming seventh season, but it won’t be his first appearance on the show as the 40-year-old appeared on The Voice before, as Team Usher's season 4 battle rounds mentor.
Recently Chris Martin joined the show's ranks, serving as an advisor on the sixth season, which is currently underway.
Gwen recently gave birth to a son, Apollo Bowie Flynn, on February 28. He was her third child with husband Gavin Rossdale, and although reports emerged that she was several months pregnant at the end of August, Gwen didn't confirm the exciting news until late October.
Christina, who is engaged to Matt Rutler, announced she is expecting her second child in February.
The Voice coach is already a mum to Max Liron, six, with her ex-husband Jordan Bratman, to who she was married from November 2005 to October 2010.