NBC has announced that the pair will start on the spring 2013 season of the show - which runs twice each year across the pond - but Xtina and Cee Lo will apparently be back in the autumn 2013 season.
Executive producer Mark Burnett explained: "Having award-winning artists as coaches means they need to be able to tour.
"Whether in the red chair or on tour, our coaches have their chairs for life. This is exactly why, after three seasons, we needed to allow them to rotate out so they can get on the road amongst their fans.
"Meanwhile, we're incredibly excited to have singular artists like Usher and Shakira joining the fold."
Aguilera's seventh album Lotus is due for release in November this year and she explained why she needed a break from The Voice.
"Since this year NBC and The Voice have decided to tape back-to-back seasons, requiring a full-year commitment, it is important for me to take season four off, allowing me to support my music that my fans have been waiting for," she said.
"By pursuing my first passion of music during the break, I am also able to come back and offer even more to my team on The Voice in the future."
Cee Lo is working on a number of projects - including a sitcom based on his own life for NBC.
He said: "It's great to also give a host of other talent the chance to experience what a joy it is to be part of what is truly the best show of them all, The Voice.
"I will return for season five and will be watching season four. NBC is home and as far as Usher and Shakira are concerned - 'mi casa su casa'."
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