Former model Mandy Rice-Davies, one of the main figures in the 1960s Profumo affair, has died from cancer at the age of 70, her publicist has said.
She - along with her friend Christine Keeler - was at the centre of the scandal which threatened to bring down Harold Macmillan's government.
Rice-Davies lived with Keeler, whose affair with war minister John Profumo prompted his resignation in 1963.
However, she never met the politician herself.
Keeler was also said to be having a relationship with Soviet defence attache Yevgeny Ivanov, although Profumo denied in the House of Commons having an affair with her.
Rice-Davies testified at the high-profile trial of Stephen Ward, an osteopath who was charged with living off the immoral earnings of her and Keeler, which exposed a web of intrigue involving the upper echelons of society.
Ward took an overdose the night before a guilty verdict was returned, and died days later.
She became notorious for claiming to have had an affair with Lord Astor and for dismissing his denial when in the witness box during the trial at the Old Bailey.
When told he had denied the affair, she famously retorted: "Well he would, wouldn't he?"
The quote was later added to the Oxford Dictionary of Quotations.
After the scandal died down, Rice-Davies continued to live the high life and later flatly denied that she had lied about her involvement with Lord Astor.
"Me? Excuse me? What was Bill [Lord Astor] doing? I didn't seduce Bill. I didn't even flutter an eyelash at him. I wasn't a temptress. He seduced me. In those days women did not leap upon men."
She also later regretted that the events of 1963 had ever happened and continued to deny that she had acted immorally.
"The only reason I still want to talk about it is that I have to fight the misconception that I was a prostitute. I don't want that to be passed on to my grandchildren. There is still a stigma."
She also insisted that she had no secrets to take to the grave.
In later years, interest in Keeler and Rice-Davies and the notorious scandal persisted, with Andrew Lloyd Webber penning a short-lived musical about Stephen Ward, which she collaborated on.
Keeler had no part in the project. Rice-Davies said the pair had not spoken for decades, saying: "I don't think she likes me."
Rice-Davies later wrote her autobiography and a novel, and also appeared on screen in a number of films and TV shows including Absolutely Fabulous.
She was played by Bridget Fonda in a 1989 movie about the Profumo affair, Scandal.
Lord Lloyd Webber said he was "deeply sad" to hear of the news of her death.
"Mandy was enormously well-read and intelligent," he said. "I will always remember discussing with her over dinner subjects as varied as Thomas Cromwell's dissolution of the monasteries and the influence of the artist Stanley Spencer on Lucian Freud.
"With a different throw of the dice, Mandy might have been head of the Royal Academy or even running the country. She became a dear friend and I will miss her."
She married three times, tying the knot with her third husband, businessman Ken Foreman, in 1988.