|Usher and Shakira|
However, they will both return for season five.
Chairman of NBC Entertainment Robert Greenblatt said: “Doing two back-to-back cycles of this show requires a tremendous amount of time, and we are happy to accommodate the commitments made by Christina and Cee Lo.
"The participants on our show benefit from our coaches' expertise and their continued success in the music business allows for significant new contributions to the contestants when they return."
Original coaches Adam Levine and Blake Shelton will remain on the panel.
Christina recently complained she has no "free time" due to 'The Voice's success.
The 'Your Body' singer admitted she only took the job initially because it meant she could be close to her four-year-old son Max, and was not expecting it to be as big as it has become.
She said: "I thought, 'It'll keep me close to my son Max in Los Angeles. I don't have to travel. Then it kind of took off and there goes my free time!"