The Queen became an ‘unlikely ally’ of Diana's despite the Princess being 'terrified' of the Monarch in her early days as part of the royal family, it's claimed.
Diana had been brought up on the Sandringham Estate and was familiar with royal etiquette throughout her childhood.
Her father served as an equerry to the Queen and both of Diana's grandmothers as ladies-in-waiting to the Queen Mother.
Diana also grew up playing with the Queen's children Andrew and Edward, closer in age to her than future husband Charles.
But, according to royal authors, Diana's familiarity with royal protocol didn't stop her being "quite terrified" of the Queen when she initially became an official part of the Firm.
Andrew Morton, author of 1992 biography, Diana: Her True Story: In Her Own Words, claimed the relationship between the Queen and her daughter-in-law was polite but formal.
He claims it was "governed by the fact that she was married to her older son and a future Monarch".
Morton adds that in the early days, "Diana was quite simply terrified of her mother-in-law" and "kept the formal obsequies—dropping a deep curtsy each time they met—but otherwise kept her distance."
However, despite the reported formality of their relationship, Diana is said to have quickly established herself as a trusted member of the family.
A year after her marriage to Charles it was Diana who attended the funeral of Grace Kelly in Monaco alone -her first solo engagement as a member of the Royal Family.
Morton says the Queen praised Diana for her "dignified manner" at the funeral.
Over time, Diana reportedly found an "unlikely ally" in the Queen as the Princess was 'supported' by her and encouraged to 'soldier on'.
Morton writes how she "found ‘perhaps a rather unlikely ally at the palace in the queen whose understanding and helpful attitude did much to encourage Diana to soldier on."
According to Morton, Diana left a lasting legacy on the royal family in that following her death they become more welcoming to newcomers.
He writes: "One of the many ironies of [the queen's] life is that Diana's impact on the royal family is measured by how much more accommodating the house of Windsor is now to newcomers.
"It is noticeable that the queen frequently joined Prince William’s bride Catherine Middleton, now the Duchess of Cambridge, in the early days of her Royal career. Certainly lessons have been learned—but at a price."
