Kelly currently serves as a coach on Season 14 of The Voice, while Jennifer previously starred on only one edition of the popular series, Season 13.
Kelly is a three-time Grammy Award winner, while Jennifer is an Oscar, Golden Globe and Grammy Award recipient.
Prior to appearing on NBC's The Voice, Jennifer also served as a coach on the U.K. version of The Voice twice, winning her first season on the series.
"The boys against the girls y'all! Team JHud and KC. We're coming after you Adam and Blake!" Kelly announced in a video on Twitter.
"We're friends but we're future frenemies. We don't mind living in the same spotlight. I love Jennifer. I can't wait to work with her! I did when I was a mentor on Season 13. I can't wait."
As for Adam and Blake, the Maroon 5 frontman and country singer have never relinquished their coaching roles since the franchise premiered back in 2011.
The Voice will feature a new panel of experts as well as a brand new batch of talent when the show returns later this year.
"We are so excited to welcome back Kelly and Jennifer, two dynamic forces who bring undeniable soul, passion and inspiration as coaches" NBC executive Paul Telegdy said in a statement.
"They each have a unique understanding of what it's like to be in the artists' shoes. Bringing these two voices together with Blake and Adam for Season 15 is sure to make this one of our best seasons yet!"
The Voice's fourteenth-season semifinals round kicks off Monday, May 14, and Kelly still has two artists in the running to be crowned the next winner -- Kaleb Lee and Brynn Cartelli.
Next week, each of the Top 8 artists will perform for home viewer votes, both an individual song and a "special duet blend," according to the network.