The ex-model, whose involvement in the Profumo Affair rocked 1960s Britain, died at the age of 75, her family said.
Her story was immortalised, first in the pages of the tabloid newspapers at a time when they were read by tens of millions, and later on screen in the 1989 film Scandal.
The affair she had with then-secretary of state for war John Profumo in the early 1960s scandalised Britain as it emerged she had also had relations with a Russian defence attache at the same time.
The fact that the revelations emerged at the height of the Cold War and led the Cabinet minister to lie to Parliament damaged the government of Harold Macmillan, and led to Harold Wilson’s Labour being elected soon after.
Keeler’s son Seymour Platt confirmed the news of her death on Facebook.
He said: “I wish to share some sad news.
“My mother, the grandmother to my beautiful little girl, passed away late last night. She suffered in the last few years with Chronic Obstructive Pulmonary Disease but lost the fight.
“As many of you know my mother, Christine Keeler, fought many fights in her eventful life, some fights she lost but some she won.
“She earned her place in British history but at a huge personal price. We are all very proud of who she was.”
Keeler had come into contact with Profumo after being introduced by society osteopath Stephen Ward, who she had met at a Soho cabaret club.
The showgirl met the Cabinet minister at a pool party at Cliveden, a Berkshire stately home then owned by Lord Astor and now a luxury hotel.
Among Stephen Ward’s other friends was military intelligence officer Yevgeny Ivanov, who was based at the Soviet Embassy, with whom Keeler also had a short relationship.
After the affairs ended, she had flings with two other men who became violent towards each other, resulting in shots being fired into Ward’s house, where Keeler was living at the time.
The arrest and subsequent conviction of the shooter, Johnny Edgecombe, brought Keeler to public attention and started a chain of events that resulted in intensive press enquiries.
As journalists continued to ask questions and rumours circulated, the Conservative chief whips made married Profumo make a statement in the House of Commons that there was “no impropriety” in his “acquaintanceship with Miss Keeler”.
When police began to investigate Ward and interviewed dozens of people who he had introduced, they found out about Keeler’s sexual relationship with the war secretary, which later forced Profumo to confess, first to his wife and later to his Cabinet colleagues, resulting in his resignation.
It was a News of the World interview that largely brought to the public’s attention her involvement in high society parties organised by Ward, and her connections to a Soviet embassy diplomat.
A number of other newspapers used the revelations to launch investigations into what some viewed as widespread immorality among the British establishment, a phenomenon that was symbolic of the shift in society taking place at the start of the swinging ’60s.
At the height of the scandal, Keeler sat for a photographic portrait by the photographer Lewis Morley – a picture of her sitting naked in a reversed Arne Jacobson chair – creating an image that is still considered one of the most famous images of the decade.
Ward was tried for being a pimp and living off the earnings of Keeler and another society girl Mandy Rice-Davies, and procuring women under 21 for sex.
He took an overdose before the trial ended and died after being found guilty, after which Keeler was convicted of perjury over claims she made in the trial of another of her former boyfriends.
She went on to be married twice and have two children but spent many years living alone, regularly tracked down by the newspapers which had paid her for her story.
Keen to give her own version of events, she wrote several books about the Profumo Affair, including the book of the film Scandal, starring Joanne Whalley.
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Her role in Ward’s life was also dramatised by composer Andrew Lloyd-Webber when he created the show Stephen Ward the Musical in 2013.
Profumo died in 2006, his funeral attended by Margaret Thatcher. Last month, it emerged he had had an affair with a glamorous Nazi spy.