The singer, who had a string of hits in the 1960s before presenting TV shows Blind Date and Surprise Surprise in the 1980s, died on Saturday, aged 72.
Terry McCann, a friend from childhood, told the BBC she said she knew she was going to die and that her beloved late husband Bobby Willis was “waiting for me”.
Mr McCann said he had seen the star in Spain during the past year, when she told him she was losing her hearing and eyesight, had arthritis and missed Willis, who died of cancer in 1999.
He said: “I wasn’t surprised when I found out she had died. The last thing she said to me was she was going blind, she showed me her hands, she had arthritis. She willed herself to die.”
He added: “Her mother went the same way. I don’t know what her mother died of but it seemed she associated it with her mother’s death and she just knew it was going to happen.
“She just said, ‘Look at me, I’m a wreck.’ I was trying to cheer her up. She knew something we didn’t.
“She knew she was going to die and she said she wasn’t going to linger like her mother.
“Her mother was ill for two years and she had the same complaint and she said she was never going to linger like that.”
Results of a post-mortem examination yesterday failed to reveal why she died.
Spanish police sources maintain her death was not suspicious but that the post-mortem results were “inconclusive”. It had been suggested Spanish police were investigating whether her death was caused by a fall from a dizzy spell, caused by a sudden temperature change in the room.
Black may have walked from an air-conditioned room into midday heat, with the change in temperature causing her to faint.
Ahead of the post-mortem, police in Spain said “everything at this stage is pointing towards her death being the result of natural causes”. Her sudden death at her home in the south of Spain has left friends, family and the British public in shock.
Tributes have been pouring in for Black, 72, led by close friends such as Sir Cliff Richard, Sir Paul McCartney and Christopher Biggins.
She rose to fame in the 1960s as an associate of The Beatles and their manager Brian Epstein.
Born Priscilla Maria Veronica White in Liverpool, she became the first woman to have her own prime-time chat show on BBC One.
Her star continued to shine brightly, and she had two number ones in 1964 – Anyone Who Had A Heart and You’re My World.
Former Beatle Sir Paul McCartney paid tribute to her from Los Angeles, saying: “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 cloakroom 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.”
And former Beatles drummer Ringo Starr said: “I just heard the news Cilla Black has left us. She was a good friend, we will all miss her. Peace to Cilla, peace and love to the family, R&B.”