“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,” he added.
The line-up change for “The Voice” follows the announcement on Sunday that rapper Nicki Minaj and country star Keith Urban will join rival Fox TV singing contest “American Idol” when it returns in January 2013. Mariah Carey has also signed up for “Idol.”
Usher, best known for his 2004 album “Confessions,” is one of the world's best-selling artists with global sales of 65 million record and seven Grammy awards.
Shakira burst onto the international pop scene with her 2006 single “Hips Don't Lie.”
“The Voice” has been a bright spot in struggling NBC's schedule since its 2011 debut, and moved to a twice a year cycle this month. Its third season opener last week notably drew more US viewers than the revamped version of Fox's “The X Factor,” with Britney Spears making her debut as a judge.
