Princess Anne, 70, has been a senior working royal for more than 50 years. She has been seen in many pieces of stunning jewellery while appearing at official royal events.
The simple piece had an embroidered veil and Princess Anne reportedly had a hand in the design of the dress.
The royal completed the look with the Queen Mary Fringe tiara, which has a special link to the Queen.
Not only was it part of the Royal Family collection, it was the same jewel the monarch wore at her wedding to Prince Phillip, 26 years before.
It has since been worn by Princess Beatrice who sported the piece at her wedding to Edoardo Mapelli Mozzi in July this year.
Speaking to Express.co.uk, president of world-leading buyer of pre-owned jewellery Circa Richard Tille commented on the tiara.
“Garrard created the Queen Mary Fringe tiara in 1919,” he explained.
“The famous jeweller had been asked to dismantle her necklace, the wedding present given to her (then Princess Mary) by Queen Victoria in 1893.
“This style of diamond fringe tiara had become fashionable during the Romanov imperial court, and later had become popular in the collections owned by the House of Windsor.
“Queen Elizabeth II didn’t wear her wedding tiara regularly as it remained in her mother’s jewel collection until she died in 2002.
“She now wears it often. While many might say this piece is priceless, some royal pieces do come up for sale now and then. When they do, royal provenance can multiply the value many times.”
Princess Anne and Mark officially divorced in 1992 and she married Timothy Laurence later that year.
Her second wedding was a much smaller affair at Balmoral Castle in Scotland.
The royal did not wear a tiara for the service.
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The royal line of succession – who outranks who?
The line of succession to the British throne dictates the order in which each member of the Royal Family would ascend to the throne.
It is also seen as a ranking of importance with the head of the line, the Queen, taking the place of ruler.
Older children come before younger children. Traditionally boys came before girls, but this law was changed on 26 March 2015 before the birth of Prince William’s first child.
Incredibly, Catholics are still excluded from the line of succession, as are children born outside of wedlock.
The royals, who usually stick to a strict protocol when appearing in public, often arrive at events in ascending order of importance, with the most important royal arriving last.
Prince Charles, 72, is currently first-in-line to the British throne, followed by Prince William, 38, his oldest son.
Then comes Prince William’s children, George, seven, Charlotte, five, and Louis, two, and they are followed by Prince Harry, 36. Prince Harry is succeeded by his son Archie Harrison, born in May 2019.