Prince Edward, the Queen and Prince Philip’s youngest son, announced his engagement to Sophie Rhys-Jones in January 1999. Edward had been dating high-flying PR executive Sophie for several years before they announced their engagement, so naturally, Edward’s proposal courted a lot of attention from the world’s press.

At their engagement photocall, Edward and Sophie were all smiles as they posed for the cameras.

But the particularly glitzy new sparkler on Sophie’s ring finger courted the most attention, and with an estimated six-figure price tag, it’s not hard to see why.

Alison Cooper, CEO of Alicia J Diamonds (www.aliciajdiamonds.com), told Express.co.uk: “This royal’s 2.05-carat, white gold engagement ring is thought to be the most expensive royal engagement ring ever purchased, with an estimated value of £105,000.”

Edward made sure to include a “romantic” element with his ring choice with two heart-shaped diamonds.

Ms Cooper added: “The sparkler features three diamonds set in white gold.

“The centre stone is an oval-cut diamond, which is romantically flanked by two heart-shaped diamonds.”

In the years before Sophie and Edward got engaged, gemstones like sapphires and rubies had become more popular with engaged royals.

Princess Diana famously received a large sapphire ring from Prince Charles, while Sarah Ferguson debuted a stunning ruby ring upon her engagement to Prince Andrew.

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A statement from Buckingham Palace read: “The Queen and the Duke of Edinburgh are delighted to announce the engagement of their youngest son, Prince Edward, to Miss Sophie Rhys-Jones.

“The couple sought the permission of their respective parents between Christmas and the New Year. Both families are thrilled at the news.

“No decision has been taken yet regarding the venue and date for the wedding.

“However, Prince Edward and Miss Rhys-Jones hope that it might be possible to use St George’s Chapel, Windsor in the late spring or summer.”

Sophie and Edward would marry at St George’s Chapel later in 1999, and the couple are still happily married today more than two decades on.