Singer and television star Naomi Judd, famous for nearly four decades as the matriarch of the country music duo the Judds, died Saturday at 76.

No cause of death was immediately given, although in a statement daughters Wynonna Judd and Ashley Judd attributed their mother’s death to “the disease of mental illness.”

“Today we sisters experienced a tragedy,” the statement said, according to the Associated Press.

“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.”

A statement from Naomi Judd’s publicist said that her husband of 32 years, Larry Strickland, “will not be making any further statements.

Naomi Judd’s family request privacy during this heartbreaking time. No additional information will be released at this time.

The announcement came the day before the Judds were set to be formally inducted into the Country Music Hall of Fame at a medallion ceremony in Nashville.

The ceremony will go ahead, with Wynonna expected to attend, according to a statement sent to Variety by a rep for the Hall.