During a visit to Hong Kong in 1989, Diana donned what has been dubbed the ‘Elvis dress’ for an engagement.
The iconic white gown was custom-made by Catherine Walker for the Princess and featured a matching white bolero jacket.
Several comparisons can be drawn between Diana’s outfit and the ensemble worn by her daughter-in-law at this week’s State Banquet.
“After Queen Mary’s death in 1953, Queen Elizabeth II sported the tiara several times in the early years of her reign, later gifting it to Princess Diana as a wedding gift.
“While Diana opted to wear the Spencer Tiara on her wedding day, the Lover’s Knot did become one of her favourites, until she returned it upon her divorce from Prince Charles.
“The tiara wouldn’t be seen again in public until 2015, when it was adopted by Princess Catherine.”
The Lover’s Knot Tiara is one of the best-known tiaras in the royal collection, and as such, it is likely worth a staggering sum.
Mr Hinds added: “No official valuation has been confirmed for the Lover’s Knot Tiara, though various estimates have placed the item at a value exceeding £1million.”
Still married to Prince Charles at the time, pictures of Diana’s outfit in 1989 showed her wearing her iconic sapphire engagement ring.
The 12-carat sparkler now belongs to Kate, and she is rarely pictured without.