Fergie, 61, added: "My greatest mentor and...person who believes in me is the Queen ？ and [she] has never faltered. I absolutely admire the incredible way Her Majesty is so modern... and how flexible, and how understanding, and how forgiving and how generous."

       Prince Andrew's ex was on the Tea With Twiggy podcast yesterday, promoting her debut Mills & Boon novel Her Heart For A Compass.

       She told model Twiggy, 71: "I think to myself that honestly my mother-in-law has been more of a mother to me than my mother."

       Fergie added: "I absolutely think there is no greater mentor because, from a little girl to now, the consistency of Her Majesty has been a great honour, it's a huge honour ？ makes me want to cry."

       Her mother Susan Barrantes left 13-year-old Fergie with her father Ronald to start a new life in Argentina with polo player Hector Barrantes. She died aged 61 in a car crash there in 1998.

       The Duchess and her ex-husband were said to have joined the Queen on holiday at Balmoral last week. It is her first proper summer break in the Scottish castle since she was cast out of the royal family in the 1990s.

       The Duke of Edinburgh, who died in April, reportedly refused to let her stay whenever he was there.