Kate and Prince William got married on April 29, 2011 and the wedding took place in Westminster.
The Duchess of Cambridge added to her ring collection on the big day by receiving a Welsh gold wedding ring.
Kate has been wearing it next to her engagement ring since the couple got married.
A few years after their ceremony, some royal fans may have noticed that she had started wearing a third ring on her finger.
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The white gold ring is said to be an eternity ring given to the royal family by Prince William to celebrate the birth of Prince George, seven.
Speaking to Express.co.uk, 77 Diamonds Managing Director Tobias Kormind suggested there might be some sweet meaning behind the gem.
He said: “The gift of an eternity ring is an extremely romantic gesture that every woman dreams of.
“It represents everlasting and everlasting love – which is why it usually features identically sized diamonds set all around the band to symbolize an everlasting bond.
“A wire and grain setting is where the gold metal edging is visible around the diamonds and there are small precious metal prongs holding each individual diamond.
“I estimate a ring like this would cost between £ 1,500 and £ 2,000 on Main Street.”
Since Prince George’s birth in 2013, Kate has worn the jewel on countless occasions.
The mother of three will wear it often on her wedding finger, as is the tradition for eternity groups.
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The royal line of succession – who surpasses whom?
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 considered a ranking of importance with the leader, the queen, taking the place of sovereign.
Older children come before younger ones. Traditionally, boys came before girls, but this law was changed on March 26, 2015, before Prince William’s first child was born.
Incredibly, Catholics are still excluded from the line of succession, as are children born out of wedlock.
Members of the Royal Family, who usually stick to 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 to the British throne, followed by Prince William, 38, his eldest son.
Next are Prince William’s children George, seven, Charlotte, five, and Louis, two, followed by Prince Harry, 36. Prince Harry is replaced by his son Archie Harrison, born in May 2019.