Aguilera said in a statement that it was important for her to take the fourth season off to concentrate on a tour that will follow the Nov. 13 release of her album "Lotus." She said she intends "to come back and offer even more to my team on 'The Voice' in the future."
Green will remain in television, developing a scripted comedy series for NBC based on his life. He will also be working on his next solo album, a new Goodie Mob album, his Las Vegas residency "Loberace," and a memoir being written by David Wild. Green said he will return for Season 5.
The announcement of a spring season confirms a report in a recent issue of Billboard magazine that "The Voice" would be moving to a full year on NBC's schedule. Coaches Adam Levine and Blake Shelton will remain through Season 4.
"Having award-winning artists as coaches means they need to be able to tour," executive producer Mark Burnett said in a statement. "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." Usher is currently on three Billboard charts with different singles. His "Scream," which peaked at No. 9, is No. 36 on the Hot 100; "Numb" is No. 31 on pop songs; and "Dive" debuted last week on the Mainstream R&B/Hip Hop songs at No. 34.
Shakira is in Barcelona recording her next album.