Delores O’Riordan of the Cranberries has died suddenly in London. Cause of death is unknown. She was 46. (Photo: Instagram)

Dolores O’Riordan, lead singer for the Irish rock group The Cranberries, died suddenly in a London hotel. Early indications suggest it was due to a drug overdose, although no cause of death has yet been established. She was 46.

The cause of death will have to be determined by an autopsy.

The Cranberries were forced to cancel tour dates in 2017 because O’Riordan was suffering from “back problems,” according to the Irish Times.

She may have been taking opioids, primarily used for pain relief, to control the problem. O’Riordan had also previously been diagnosed as bi-polar and subject to bouts of depression.

Dave Davies, a member of the iconic English rock band The Kinks, said on social media that he had talked with O’Riordan only a few weeks ago.

“I’m really shocked that #DoloresORiordan has passed so suddenly. I was talking to her a couple weeks before Christmas she seemed happy and well – we even spoke about maybe writing some songs together – unbelievable god bless her,” he Tweeted.

The singer was found dead in her London hotel room Monday (Jan. 15). She was in London for a recording session. A spokesperson confirmed her death.

“Irish and international singer Dolores O’Riordan has died suddenly in London today. She was 46 years old. The lead singer with the Irish band The Cranberries, was in London for a short recording session. No further details are available at this time,” she said.

The Cranberries formed in the early ’90s, with Dolores as lead singer. She was joined by guitarist Noel Hogan, bassist Mike Hogan and drummer Fergal Lawler.

Their first big hit was the single “Linger.”

Their 1993 debut LP Everybody Else Is Doing It, So Why Can’t We? rocketed them to fame in Britain, America and Europe.

The band’s second album No Need To Argue was released in 1994 and became a global smash. It included singles “Zombie,” “I Can’t Be With You” and “Ode To My Family.”

The band followed that record up with five more albums with the most recent release being 2017’s Something Else.

In recent years, Dolores also fronted a band called D.A.R.K. and was in London working on an unknown project at the time of her death.

She split from husband Don,the former tour manager for Duran Duran,in 2014 after 20 years together. They have three children, Taylor, 20, Molly, 16, and Dakota, 12.

The rock artist was raised and remained a Catholic and she had the honor of meeting the late Pope John Paul II and Pope Benedict XVI and performed at the Vatican on several occasions.

Check out the video below, let us know your thoughts and be sure to follow IM on Twitter for the latest music news.