user: Problem: Friends, fans and fellow entertainers have spoken of their shock at her death.
Prime Minister David Cameron paid tribute on Twitter to her "huge talent" and "significant contribution to public life".
Bruce Forsyth expressed his shock to the BBC, saying he still thought of Black as "just a kid" and that "72 is no age to leave us all".
"I can't really take it in at the moment. I'm in shock," he said.
"So many people will be so upset. She had such a following with all the shows she did.
"She had that common touch when you get to everybody with your career. She will be greatly missed by all."
Gloria Hunniford said: "It's a total shock, actually it's a bit of disbelief. It was two weeks ago today that we were at a mutual friend's barbecue."
She said she knew "Cilla had little niggly things that were wrong with her".
"For example she had a bit of trouble with her eyesight and her hearing and a bit of trouble with her knee and walking, but then anybody over 70 will recognise all of those," she said.
"But there was nothing on that day, only two weeks ago, that would have suggested that she had anything that was life threatening. I'm very saddened."
She added: "What I loved about her was she had that common touch, that Liverpool marvellous touch, where she could talk to anybody and have a bit of fun."
DJ Tony Blackburn said that "it just doesn't seem possible that she is no longer with us".
He told the BBC News Channel: "She was lovely. She just wanted everyone to do well and have fun.
"She had a great sense of humour. What you saw on television was Cilla Black. There was no pretence about her at all and to suddenly hear today that she's no longer with us is a real shock.
"I think people forget how important she was in the early days of pop music. We forget now how many hit records she had. She had a wonderful career."
Barbara Windsor, who had known Black for many years, said: "Oh it's awful.
"I was only with her a couple of weeks ago. I've seen her twice in the last few weeks and as always she looked immaculate. That was the thing about Cilla, she always looked spot-on.
"But I knew she wasn't very well. She didn't look or seem very well. But I'm so desperately sad."
Sir Paul McCartney said: "Such a shock to hear about Cilla's passing. She was a lovely girl who infected everyone with her great spirit.
"From first meeting her as a cloak room girl at the Cavern in Liverpool, to seeing her many times since, she always had a fun-loving dignity that made her a great pleasure to be around.
"She had a fine distinctive voice and was always a bit of a laugh. It was a privilege to know and love her."
Singer and broadcaster Des O'Connor said: "If ever the words 'the one and only' applied to anyone it was Cilla. She really was unique.
"As a friend she was always fun to be with, kind, generous and caring, a very special lady. We will all miss you Cilla more than words can say."
Singer Sir Cliff Richard said he would miss his "outrageous" friend dearly.
"Some people will always be with us and Cilla is one of those people," he said.
"I will always think of her as outrageous, funny, incredibly gifted but above all full of heart. She was a very special person, and I have lost a very wonderful friend, I will miss her dearly. God bless her."
Many entertainers took to Twitter to pay tribute to Black:
What was that article about?

A: Tributes have been paid to Cilla Black, one of Britain's best-loved entertainers, who has died at the age of 72.


Text: He told Radio 4's Today that Philip Hammond, Mr Osborne's successor, should change tack and raise public spending.
"It's clear he will spend more," the former Greek finance minister said.
Mr Hammond is to reveal his spending plans at next week's Conservative Party conference in Birmingham.
Mr Varoufakis, in London for the Institute of Directors' annual conference, said each time Mr Osborne had cut spending, he had been forced to push back his budget targets.
However, his criticism of Mr Osborne has come under attack on Twitter. "Kettle 'particularly inept at not being black', says Pot" and "Takes one to know one" were two of the kinder comments.
The maverick former Greek minister, who served from January to June last year and gained notoriety for his confrontational approach to Greece's creditors as well as his habit of wearing leather jackets and riding a motorcycle, said he had spoken "frequently" to John McDonnell, the shadow chancellor.
Mr McDonnell unveiled Labour's economic plans at the party's conference earlier this week, including a £250bn infrastructure package and £10 an hour minimum wage.
"I have spoken to John McDonnell many times," Mr Varoufakis said. "And we agree that the one thing Britain needs is investment."
Mr Varoufakis said there was an estimated £900bn "trapped doing nothing" in City financial institutions and that money needed to be put to work.
He said he foresaw a Europe split into two economic blocs - one in the north, centred on Germany, and another in the south.
Referring to Greece, Mr Varoufakis said he agreed with recent criticisms of the European creditors' negotiation position by the International Monetary Fund - which is itself a creditor.
On Friday, the IMF said European plans to force Greece to operate a large budget surplus were unrealistic and that it needed extra debt relief if it was to return to financial health.
"My country is in a debt trap and it needs a much smaller budget surplus target if it is ever to escape," he said.
Mr Varoufakis also said he expected the eurozone eventually to implode, citing problems in the German and Italian banking systems as a big threat to its stability.
summary:

assistant: George Osborne will be remembered as a "particularly inept" chancellor whose pursuit of austerity in an attempt to rein in Britain's deficit was doomed to failure, according to Yanis Varoufakis.