To make matters worse for the couple, the sudden and tragic passing of Diana only made the British public turn on the lovers, and according to a royal biographer, the pair were even planning to reveal their relationship to the public for the first time with a "spectacular party" just before the car accident in Paris that took Diana's life.
Royal biographer Penny Junor in her book The Firm, details how Charles and Camilla were planning to go public with their coupling before the sudden tragedy in 1997.
"Before Diana’s death they had been on the verge of coming out," Ms Junor writes.
[Camilla’s] birthday party at Highgrove had gone well; Diana, meanwhile, had been attracting increasingly hostile publicity for her flirtatious behaviour in the South of France with Dodi al Fayed.
“(PR advisor) Alan Kilkenny was easing Camilla gradually out of the shadows."
“They were two weeks away from a spectacular party to raise money for the national Osteoporosis Society at Camilla’s sister Annabel’s antiques business in Dorset.
“700 invitations had been sent out, at £100 apiece, and although nothing was official there were plans for the prince to pay a surprise visit to the party.
“It would have been a giant step along the path to making Camilla a legitimate part of the prince’s life – the phrase he used time and again – which was his ultimate goal."
Ms Junor ended: “But those and every other plan screeched to a halted that Sunday in August when Britons awoke to the shocking news that Diana, Princess of Wales, had been killed in a car crash.”