The series, in which singers compete for a Warner Bros. Records contract, is set to premiere on NBC June 9.
Jewel was last season's "Nashville Star" host.
This season, she joins the program's previously announced judge/mentor John Rich -- the producer of her latest album, "Perfectly Clear" -- and one half of the country duo Big & Rich, the network said.
"As a young artist, I really benefited from having great mentors like Bob Dylan and Merle Haggard. They took me under their wings and encouraged me to stand up for things that, as an artist, are important. They constantly reminded me that an artist's only concern is being great, not being famous. If you are truly great, success should follow," Jewel said in a statement. "I am so excited to be a part of 'Nashville Star,' to help mentor young artists and cultivate their singing, songwriting and playing and to encourage and continue that tradition."
Singer-songwriter Billy Ray Cyrus has been named this season's "Nashville Star" host.