Sinead O’Connor, known for her 1990 hit “Nothing Compares 2 U,” is dead at the age of 56.

The cause of death was not immediately known, but the Irish singer’s family released the following statement:

“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.”

She was best known for her single “Nothing Compares 2 U,” which was a world-wide No. 1 hit.

Irish PM Leo Varadkar said, per the BBC, her music “was loved around the world and her talent was unmatched and beyond compare.”

“Nothing Compares 2 U” received three Grammy nominations and was the featured track off her acclaimed album “I Do Not Want What I Haven’t Got,” which helped lead Rolling Stone to name her Artist of the Year in 1991.

According to The Associated Press, she said she shaved her head in response to record executives pressuring her to be conventionally glamorous — but her political and cultural stances and troubled private life often overshadowed her music.

• She feuded with Frank Sinatra over her refusal to allow the playing of “The Star-Spangled Banner” at one of her shows.
• She accused Prince of physically threatening her.
• In 1989 she declared her support for the Irish Republican Army, a statement she retracted a year later.
• She skipped the Grammy ceremony, saying it was too commercialized.

She was also a critic of the Catholic Church. O’Connor made headlines in October 1992 when she tore up a photo of Pope John Paul II while appearing live on NBC’s “Saturday Night Live” and denounced the church as the enemy.

O’Connor’s son Shane, 17, died last year, days after he was reported missing. Following her son’s death, O’Connor took to social media and wrote he had “decided to end his earthly struggle” and requested “no-one follows his example,” per the BBC.

The Associated Press contributed to this report.