Queen Elizabeth II and Princess Anne attend a function at the Hotel Imperial in Vienna, during a State Visit to Austria, 7th May 1969

Queen Elizabeth II and Princess Anne attend a function at the Hotel Imperial in Vienna, during a State Visit to Austria, 7th May 1969Photo by Fox Photos/Hulton Archive/Getty Images

Have you ever wondered why only some royals wear tiaras and others never have? We know!

Kate, Meghan and Princess Eugenie have all been photographed in tiaras over the past year, often borrowed from the Queen, yet Princess Beatrice has yet to be photographed wearing a borrowed headpiece. And now we know why. 

Read more: Will Kate inherit this title when the Queen dies?

In an interview with Town and Country jewellery expert Geoffrey Munn explained the tiara’s hidden meaning.

He said: “Any woman may wear one, but ancient tradition has it that they must be a bride or already married.

“The tiara has its roots in classical antiquity and was seen as an emblem of the loss of innocence to the crowning of love.

Queen Elizabeth II at a Royal Gala performance at Covent Garden during her Silver Jubilee celebrations, 30th May 1977. (Photo by Hulton Archive/Getty Images)

Queen Elizabeth II at a Royal Gala performance at Covent Garden during her Silver Jubilee celebrations, 30th May 1977. (Photo by Hulton Archive/Getty Images)

“One of the mainstays of European royalty and aristocracy is to do what you have always done and formal dress, jewellery, and tiaras are just part of this.”

Which explains why for her wedding the Duchess of Cambridge wore a Cartier scroll tiara, featuring 49 baguette-cut diamonds as well as 739 brilliant-cut diamonds which was estimated to be worth between £750k and £1.2 million.

TRH Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge smile following their marriage at Westminster Abbey on April 29, 2011 in London, England. Image: Getty

TRH Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge smile following their marriage at Westminster Abbey on April 29, 2011 in London, England. Image: Getty

The Duchess of Sussex also wore a Cartier tiara, her's was an art deco bandeau of diamonds and valued at more than £2 million. 

However, Princess Eugenie wore the most expensive tiara of recent royal weddings, pairing her wedding dress with a borrowed 93.70 carats cabochon emerald tiara, which was hand made by Boucheron in 1919. The tiara was valued at almost £10 million.

Princess Eugenie of York arrives to be wed to Mr. Jack Brooksbank at St. George's Chapel on October 12, 2018 in Windsor, England. (Photo by Andrew Matthews - WPA Pool/Getty Images)

Princess Eugenie of York arrives to be wed to Mr. Jack Brooksbank at St. George's Chapel on October 12, 2018 in Windsor, England. (Photo by Andrew Matthews - WPA Pool/Getty Images)

Mr Munn went on to explain that despite being a rather large piece of jewellery, the tiara has never been a symbol of wealth or position, saying: "It is not the owner that triggers the wearing of tiaras but the event at which they are worn.

“In the past they were worn at full evening dress occasions, which are now known as ‘white tie.’

“Sometimes the invitation would say ‘Tiaras will be worn. This is virtually over now."

So the question remains, will Princess Beatrice adopt the tradition of wearing a tiara for her wedding next year?

Read more: Will Princess Beatrice's title change after she gets married?