She was found ‘unresponsive’ after police were called to her flat in Herne Hill, South East London, in July last year.
‘This is to confirm that Ms O’Connor died of natural causes,” a spokesperson for Southwark Coroners Court told MailOnline.
The news comes after details of the line-up were announced for a tribute concert for her and Shane MacGowan, who also recently passed away. Artists such as cat Power, David Gray, Dropkick Murphys and Glen Hansard will perform at the legendary Carnegie Hall in New York on March 20.
What does ‘natural causes’ actually mean?
‘We were one soul in two halves. He was the only person who ever loved me unconditionally. I’m lost in the bardo without him.”
Police were called to Ms O’Connor’s home in the SE24 area of London, which covers the upmarket Herne Hill and is between Brixton and Dulwich, just before 11am on July 26.
Notable residents of SE24 include actors Mark Rylance, Olivia Colman and James Nesbitt.
It came as MailOnline revealed that Ms O’Connor had just moved back London in early July – she called the city her “home” – and described her hope and excitement at seeing the ballet and writing new songs in the days before she died.
She also said on Facebook that she wanted to go on tour next year in a positive post from a fortnight ago in which she declared: ‘The b**** is back’, with fans hoping the fragile star would overcome the depression and suicidal thoughts that haunted her , defeated for so many years, especially after the death of her son Shane last year at the age of 17.
Tributes poured in for Ms O’Connor after her death was announced in July.
Irish President Michael D. Higgins praised O’Connor’s “extraordinarily beautiful, unique voice” and said he hoped “her spirit may find the peace she sought in so many different ways.”
He said: “May I extend my deepest condolences to Sinéad O’Connor’s father John, the members of her family and everyone with whom she shared her life.
‘My first reaction when I heard the news of Sinéad’s loss was that I remembered her extraordinarily beautiful, unique voice.
‘What stood out in all her recordings and in all her performances was the authenticity of the performance, while her dedication to the performance of the song and its meaning was total.
“For those of us who were privileged to know her, one could not help but always be struck by the depth of her fearless dedication to the important issues she brought to public attention, no matter how uncomfortable those truths were.
Ms O’Connor filmed her new flat and seemed happy to have just moved back to London at the beginning of July – the last time she was seen
During a video tour of her apartment, she showed her guitar on the wall and said she was writing new songs
She said she was happy to be home in London and showed fans sunflowers from a friend
Ms O’Connor also tweeted her excitement at seeing a screening of Rudolf Nureyev’s performance
The block in south-east London where Mrs O’Connor had recently moved
‘What Ireland has lost at such a relatively young age is one of our greatest and most gifted composers, songwriters and performers of recent decades, someone who had a unique talent and an extraordinary connection with her audiences, who all gave so much love and felt warmth for her.
‘The way she was able to move between different forms of art was a special achievement, as was the way her voice traveled around the world and how it was received.
‘Her achievements include a body of work for film through the production of perfectly chosen and critically acclaimed texts.
‘Sinéad O’Connor’s voice and delivery were original and extraordinary in so many ways and left a deep, profound impression that to have achieved all that she did while carrying the burden that she did.
“Her contribution echoes the great contributions of Irish women who have contributed to our lives, culture and history in their own unique but unforgettable ways.
“May her spirit find the peace she sought in so many ways.”
Sinead O’Connor’s grave is pictured in Deansgrange Cemetery in Bray, Co Wicklow
Pictured: Onlookers applaud as Sinead O’Connor’s coffin passes her former home
In her latest tweet, O’Connor posted a photo of Shane and said, “I’ve been living as an undead night creature ever since. He was the love of my life, the lamp of my soul’
She added: “We were one soul in two halves. He was the only person who ever loved me unconditionally.” Pictured: Sinead O’Connor on stage at the Olympic Ballroom, Dublin, in March 1988
Irish Prime Minister Leo Varadkar said: “I am truly sorry to hear of the passing of Sinéad O’Connor.
“Her music was loved around the world and her talent was unparalleled and beyond comparison.
“Condolences to her family, her friends and everyone who loved her music.
‘Ar dheis Dé go Raibh a hAnam. (At the right hand of God rests her soul/Rest in peace.)”
Tanaiste Micheál Martin said he was “devastated” when he heard of O’Connor’s death.
In the years after her breakthrough, she wrote even more hits, including You Made Me The Thief Of Your Heart – for the soundtrack of the Daniel Day-Lewis film In the Name of the Father – Drink Before The War and This Is The Day
He added: “One of our greatest musical icons, and someone much loved by the people of Ireland and beyond.
“Our thoughts go out to her children, her family, friends and all who knew and loved her.”
The Irish Embassy in America said: ‘Deeply saddened to learn of the passing of Sinéad O’Connor. An amazing artist whose music brought so much joy to people all over the world.”
Comedian Dara O’Briain said: ‘Ah s****, Sinead O’Connor has died. That’s just very sad news. Poor thing. I hope she realized how much love there was for her.’