The Duchess of Edinburgh was one of the late Queen's closest confidantes. Over the years, a strong bond developed between the royals, which many onlookers likened to that between a mother and daughter.
Indeed, their bond was so close that Sophie began referring to the Queen as 'mama'.
But there were some teething issues along the way - including one moment which saw the monarch give Sophie a 'look' she wouldn't forget.
Sophie - who has been married to Prince Edward since June 1999 - recalled the incident in the 2013 ITV documentary Our Queen.
Reflecting on the rules surrounding attendance at a state banquet, the Duchess explained that she had found it tricky to figure out where she was meant to be sitting.
Duchess Sophie's mistake - and the Queen's reaction
Sophie admitted: "The moment you go into a ballroom at Buckingham Palace it's terrifying. You see a wall of people and you then think, 'Oh help, I've got to find my chair'.
"Because I'm normally walking in with somebody who's never visited before, they don’t know what they meant to be doing and I have to say on more than one occasion I've managed to sit in the wrong seat."
© UK Press via Getty ImagesShe then laughed about the time she struggled to find her place just as the Queen was preparing to deliver a speech.
The monarch spotted her daughter-in-law still negotiating seating arrangements - and was less than impressed.
Sophie said: "But I shan't forget the look that I got when I couldn't find my chair and [the Queen] was looking to do her speech.
"I decided I might study my notes a little more carefully next time."
A mother-daughter bond
Happily, the mishap didn't get in the way of the two women's friendship. It was to Sophie that the monarch turned after the death of Prince Philip, with royal insiders describing the Duchess as being a 'rock' to the Queen.
© Getty ImagesFurthermore, Sophie lived just ten miles away from Windsor Castle at Bagshot Park, and would regularly visit the Queen and spoke to her on the phone daily.
Sophie and Edward's major change at home
Sophie and husband Edward have been married for 27 years and are the proud parents of two children, Lady Louise, 22, and James, Earl of Wessex, 18.
But the royal couple have now become empty nesters for the very first time. Their daughter, Lady Louise, has been away at university for the past few years, but this month the time came for her younger sibling James, Earl of Wessex to enroll in his own university studies.
© Photo: Getty ImagesJames recently started his undergraduate journey at the Royal Agricultural University in Cirencester, Gloucestershire, where he will study Rural Land & Property Management.
The teen opted to forgo a gap year and head to university straight after completing his A-levels. The decision was confirmed in a statement by Buckingham Palace.
"Having achieved the grades he needed, The Earl of Wessex will be going to the Royal Agricultural University to study Rural Land & Property Management. He will head straight there without taking a year out," the Palace said. James' three-year degree will focus on estate management, rural business, and consultancy.
The young royal will be swapping his family home, Bagshot Park, for Cotswolds living. The university campus, set in Cirencester, has a range of accommodation, including catering options for students. Undergraduates often spend their first year living at university halls.
His sister just finished her university journey
Earlier in the summer, James' big sister, Lady Louise Windsor, graduated from the University of St Andrews with an English degree.
Prince Edward and Duchess Sophie were the picture of proud parents as they beamed alongside their daughter in her graduation portraits, taken at the University House following the ceremony.
"Congratulations to Lady Louise on her graduation from St Andrews University!" the royal family congratulated Louise on her four-year undergraduate journey.
