Naomi Judd, whose singing partnership with daughter Wynonna was one of the most popular country duos of the 1980s, died Saturday outside Nashville. She was 76.

Wynonna Judd and her sister, actress Ashley Judd, released a statement that read, “Today we sisters experienced a tragedy. We lost our beautiful mother to the disease of mental illness. We are shattered. We are navigating profound grief and know that as we loved her, she was loved by her public. We are in unknown territory.”

No cause was given and Naomi Judd’s publicist said Judd’s husband of 32 years, Larry Strickland, “will not be making any further statements. Naomi Judd’s family requests privacy during this heartbreaking time. No additional information will be released at this time.”

The Judds landed 23 singles on the country Top 40 charts between 1983 and 1991; 14 went to No. 1. In 1985 and ’86, they had six straight singles go to #1. Their first three albums topped the country chart; their Curb/RCA debut, 1984’s Why Not Me, was certified double platinum, while the other two were million-sellers.

The Judds won five Grammy Awards in the Country Performance by a Duo or Group with Vocal category between 1985 and 1992.

They took home the CMA Awards’ best duo/group trophy every year from 1985-91, winning nine awards overall; they have eight ACM Awards, including the top vocal duo trophy for every year from 1984 through 1990.

The Judds were scheduled to be inducted into the Country Music Hall of Fame in Nashville on Sunday. Naomi and Wynonna were also scheduled to do a 10-date farewell tour beginning 9/30.

Born Diana Judd in Kentucky, she changed her name to Naomi and put her mother/daughter act onstage in Tennessee while also working as a nurse. The father of a child she cared for was a producer who helped get them a deal with Curb/RCA.

The Judds were a hit out of the box, scoring their first #1 with “Mama He’s Crazy” in 1984.

They disbanded after Naomi was diagnosed with hepatitis C, reuniting for a handful of performances beginning in 1998; they embarked on a 29-show reunion tour in 2011.

Naomi Judd also worked as an actress, appeared on reality shows and wrote nine books over the last three decades.