In a statement, her family said it was with "great sadness that we announce the passing of our beloved Sinead. Her family and friends are devastated and have requested privacy at this very difficult time," Irish national broadcaster RTE reported.

In 2018, the outspoken Irish singer converted to Islam and changed her name to Shuhada.

O'Connor's 1990 hit "Nothing Compares 2 U" became a global hit, with her haunting voice, shaved head and single-tone outfits turning her into both an enigmatic and captivating figure.

But her career began to falter after she tore up a picture of the late Pope John Paul II while appearing as a musical guest on US television in 1992.

She said she was protesting sexual abuse in the Catholic Church, but her gesture was roundly condemned in the media and she was eventually forced to apologise.

Yet her fight against the Catholic Church continued, and in 1999 O'Connor was ordained as a priest by a breakaway church based in the French city of Lourdes.

Catholicism does not sanction priesthood for women.

O'Connor told Billboard magazine in 2014 that she was still ordained but had stepped away from the priesthood because "I'm not interested in causing more trouble than I already am".