Wynonna and her actress sister Ashley shared their "deep grief" on their Instagram accounts.
“We have lost our wonderful mother to mental illness,” they said, without further details.
Naomi and Wynonna Judd formed their duo in the late 1970s, winning numerous awards including five Grammys.
Some of the mother-daughter couple's most popular songs include "Love Can Build A Bridge", "Mama He's Crazy", and "Girls' Night Out".
The duo, which had reunited many times for tours and special performances despite breaking up in 1983, officially disbanded in 1991 when Naomi was diagnosed with hepatitis C.
Mother and daughter were set to tour again this fall for the first time in more than a decade and on Friday, the Country Music Hall of Fame announced that The Judds would join their ranks on May 1 for helping "bring country back to its roots. in the 1980s with light and melodious songs influenced by traditional folk music, acoustic blues, and for its family harmony".
© 2022 AFP