Prince Charles told Queen Elizabeth and other royal family members that his second wife Camilla Parker Bowles was "non-negotiable" part of his life, according to the book written by Penny Junor title The Duchess: Untold Story.

Junor described the things that happened following Princess Diana's tragic death back in 1997. It noted that Queen Elizabeth wanted Camilla gone during those times, and she also wanted her to be out of Prince Charles' life even when the Princess of Wales was still alive.

Junor wrote in the book that it was nothing personal. Queen Elizabeth has been very fond of Camilla when she was still married to Andrew Parker Bowles. However, Her Majesty allegedly believed that the Duchess of Cornwall was responsible for all the disasters that happened to Prince Charles after their marriage.

But then, the Prince of Wales reportedly made it clear to everyone, particularly to his mother, that Camilla will always be a part of his life and she is "non-negotiable." The book added that the Duchess of Cornwall changed the life of Prince Charles and she's supporting the future king especially during difficult times of his life.

There were times when Prince Charles reportedly needed support so bad, and Camilla was the one who's there for him and rescued him from the depths of depression. According to Junor, Camilla was always there for the Prince and she showed him love, comfort, approval, and tenderness.

So, Prince Charles reportedly became "infuriated" with Queen Elizabeth when she hosted his 50th birthday celebration back in 1998. Since Princess Diana has only been dead for about a year that time, Her Majesty didn't invite Camilla on the occasion.

That night, as per Junor, the public display of warmth belied the real situation. Prince Charles was reportedly infuriated because his mother has been continuously showing hostility towards the woman he really loves.

But now, many years had passed, things got better for the Prince of Wales and the Duchess of Cornwall. In 2005, Queen Elizabeth allowed them to get married in a civil ceremony. It seems like things also get better between the two ladies, as they reportedly spend time together regularly.

In fact, they were frequently seen attending royal engagements together, and they have been photographed laughing and talking in public. As for Prince William and Prince Harry, they initially struggled to accept Camilla in their lives following their mom's death, but the three has now a good relationship as well.