After her marriage to Prince Charles collapsed in a blaze of controversy in the early 1990s, Princess Diana's relationship with the royal family would never be the same again.
But even in the early days of their relationship, the Princess of Wales was taking cues from Queen Elizabeth on how to raise her sons Prince William and Prince Harry - by doing the exact opposite of what her reigning mother-in-law did with her own children.
According to royal biographer and Diana's confidant Andrew Morton the Princess was greatly affected by a photograph from Prince Charles' childhood, taken in 1954 when the Queen returned from her longest ever Commonwealth tour which took her across 13 countries and away from her young children for almost seven months.
Writing in his 2011 work William and Catherine, Mr Morton said: "On greeting her eldest son [Charles], then aged five, after an absence of six months, the new Queen shook his hand rather than hugging him.
"That image was to have a lasting effect on Diana, Princess of Wales."
Watch this video to see how Diana was a royal rule breaker from the minute Prince William was born:
Diana's warmth and informal attitude to parenthood clashed with the traditional royal behaviour and contrasted dramatically with the Queen's approach to mothering, Express.co.uk reports.
So different was her stance, Diana made history by taking then-toddler William along with her and Charles on their royal tour of Australia in 1983.
Earlier this week, the Duke of Cambridge opened up about the pain he felt after Diana's tragic death in 1997.
Speaking in a new BBC documentary on mental health, the father-of-three said: "I think when you are bereaved at a very young age, anytime really, but particularly at a young age - I can resonate closely to that - you feel a pain like no other pain."