A Spanish police spokesperson told The Daily Telegraph: "I can confirm the death of British national Priscilla White, aged 72."
"We are still awaiting autopsy results but everything at this stage is pointing towards her death being the result of natural causes."
In recent years, she has been vocal about suffering from arthritis and hearing problems and flew to her Spanish villa with her one of her sons last week.
Cilla is regarded as one of the most cherished presenters in British broadcasting history and was a successful singer with number one Anyone Who Had A Heart in 1964, which was one of the biggest hits of the decade.
As the much-loved entertainer approached her 71st birthday last year, she said that 75 might be an okay age to die.
She became one of the nation's favourite entertainers after transforming herself from a successful singer in the 1960s to the front woman on shows such as Blind Date and Surprise! Surprise!
An associate of The Beatles and their manager Brian Epstein in the early 1960s, she scored two number ones in 1964 - Anyone Who Had A Heart and You're My World - as well as enjoying many other hits, before going on to concentrate on TV.
She went on to host more than 500 editions of her programmes and was the first woman to have her own prime-time chat show on BBC1.
She hosted Blind Date from 1985 to 2005 and was made an OBE in 1997.
The life of the entertainer was portrayed in an ITV biopic last year, which followed the story of the typist's rise to fame.
Cilla, which starred Sheridan Smith and pulled in more than seven million viewers, propelled the singer briefly back in to the music charts with Anyone Who Had A Heart.
Dame Joan Collins has led tributes to Cilla Black.
Collins expressed her sadness on Twitter: "I am so sad and shocked by news about my good friend Cilla. She was a resplendent and rare talent. RIP."
Fellow TV presenter and friend Paul O'Grady struggled to believe the news.
"Please tell me this isn't true? We've been friends for nearly 20 years. She's like my sister," he told the Liverpool Echo.
"Apart from her hearing she was all right. We had a week together in Barbados at the beginning of the year and I saw her on my birthday.
"I thought she was well. I can't believe it to tell you the truth."
Her colleague on Surprise Surprise, Bob Carolgees, first worked with Cilla over 40 years ago.
"This is shocking news, I first worked with Cilla in summer season nearly 40 years ago and went on to work with her for almost 10 years on Surprise Surprise along with summer season and pantomime," he said.
"She has been taken far too early but can now be with her beloved Bobby. Thoughts to all her family."
TV personality Carol Vorderman said she was "deeply shocked" to learn of Black's death.
"I hope you are now at peace lovely lady. Thank you for the lunches and the laughs x," she tweeted.
Surprise, Surprise presenter Holly Willoughby posted a photo of her and Black together on the show, writing: "This photo is even more special to me now...."
Before that she wrote a touching message saying: "So so sad to hear the news that we have lost one of my heroes, Cilla you were one incredible lady! Sending all my love to her family. X."
Gabby Logan called her the "complete entertainer/host in an era when everyone watched TV. She was a trail blazer. RIP Cilla."
Loose Women's Carol McGiffin also paid tribute on social media, writing: "Feel privileged to have worked with her, she was hilarious and she really knew how to live. She will be missed."