Although specific details have yet to be released, it is understood that the star died during the night while spending time in her home in Marbella.
The mum-of-three, who rose to fame as a singer in the 1960s, quickly became a household name and starred in a number of long-running television shows including Blind Date and Surprise Surprise.
Cilla, who had recently commented on the ageing process, said she was becoming more aware of her own fragility, saying: "Seventy-five is a good age to go. If things are starting to drop off - like the hearing - and I’ve got twinges in the morning, I do think that."
Confirming the tragic news, a spokesperson for Spanish police said: "We are still awaiting autopsy results but everything at this stage is pointing towards her death being the result of natural causes."
Born Priscilla Maria Veronica White in May 1943, the much-loved star enjoyed a career which spanned over fifty years and shared three sons named Robert, Ben and Jack with her late husband, Bobby.
She will be greatly missed.
