LONDON (AP) — Sinéad O’Connor, the gifted Irish singer-songwriter who became a superstar in her mid-20s and was known as much for her private struggles and provocative actions as for her fierce and expressive music, has died at 56.

“It is with great sadness that we announce the passing of our beloved Sinéad. Her family and friends are devastated and have requested privacy at this very difficult time,” the singer’s family said in a statement reported Wednesday by the BBC and RTE. No cause was disclosed.

When her teenage son Shane died by suicide last year, O’Connor tweeted there was “no point living without him” and she was soon hospitalized. Her final tweet, sent July 17, read: “For all mothers of Suicided children,” and linked to a Tibetan compassion mantra.

Recognizable by her shaved head and with a multi-octave mezzo soprano of extraordinary emotional range, O’Connor began her career singing on the streets of Dublin and soon rose to international fame.