The star's publicist confirmed her tragic death saying: "Family members are devastated to hear the breaking news and have requested privacy at this very hard time".
Her three Cranberries bandmates said in a tweet that they were devastated at the passing of an "extraordinary talent". Suffice to say, I am very sad to lose someone who meant so much to me and to many people across the world.
O'Riordan defined the sound of The Cranberries - with hit songs like "Linger", "Salvation" and "Zombie".
Dolores O'Riordan, the lead singer of Irish band The Cranberries, has died suddenly aged 46. Her publicist announced her passing on Monday afternoon, simply stating: "No further details are available at this time".
Michael O'Dwyer who knows the O'Riordan family said he had been stunned to hear the news of her sudden death. "A 46-year-old woman was pronounced dead at the scene", A spokeswoman for the police said in a statement issued to the Guardian.
Now the Metropolitan Police have confirmed they are not treating her death as suspicious and said the case has been handed to the coroner's office.
Meanwhile, fans have flocked to the singer's native Limerick to pay tribute to her and to sign a book of condolence opened for The Cranberries singer at the County Council's Corporate Headquarters at Merchant's Quay in Limerick City.More news: Keeping Up With the Meltdown and Spectre Bugs
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Paramore vocalist Hayley Williams said on Twitter that her favourite Cranberries track was I Will Always, adding: "I have never not cried while listening, so here we go".
In 2014, O'Riordan was accused of assaulting three police officers and a flight attendant during a flight from NY to Ireland. "Dolores and the band are very disappointed that it has come to this and send their honest apologies to all fans and ticket holders, and hope to see you all again in the future when Dolores is well again". "My heart goes out to her children, I hope they can find some peace despite this tragic event".
However, the lead single Zombie was a huge departure from The Cranberries' usual fare - not only breaking into angsty grunge, but drawing on a recent tragedy for a visceral protest song.
SPOTIFY say that plays of The Cranberries hits have gone up almost a thousand percent since news of the passing of singer Dolores O'Riordan.
"She kept the links with Limerick".
The Cranberries broke up in 2002, when O'Riordan left the band - but not before they had sold some 35 million albums worldwide.
Eleven Seven Music CEO Allen Kovac also released a statement.