The Princess of Wales wore a tiara for the very first time on her wedding day, but did you know that it was a favourite of The Princess Royal and the late Princess Margaret?
On her marriage to Prince William in 2011, Kate was loaned the Carter Halo tiara from the late Queen Elizabeth II. Her father, King George VI, first commissioned Cartier to design the tiara for his wife, the Queen Mother, in 1936.
The headpiece, which features 739 brilliants and 149 baton diamonds, was passed down to Princess Elizabeth on her 18th, but the late Queen was never pictured wearing it publicly.
Instead, it became one of her younger sister Princess Margaret's go-to tiaras.
Margaret, who would have turned 93 today, wore the sparkling jewels for the first time in 1948 during the inauguration celebrations for Queen Juliana of the Netherlands.
She continued to wear the headpiece throughout the 1940s and 1950s, most notably at Queen Elizabeth II's 1953 coronation.
Following her marriage to Antony Armstrong-Jones in 1960, Princess Margaret opted to wear her wedding jewels, the Poltimore tiara, more often.
And when Princess Anne made her tiara debut at the age of 17 in 1967, it was the Cartier Halo she wore for the state opening of Parliament.
She also frequently wore the headpiece for evening events such as film premieres, charity dinners and balls in the 1960s and 1970s.
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The Cartier Halo tiara was then not seen for several years until Kate's marriage to William. Take a look back at some of the most beautiful royal wedding tiaras through history...
The royal wedding is the only time that the Princess of Wales has worn her wedding tiara. Since then, she has been loaned the Lotus Flower tiara and the Lover's Knot tiara, a headpiece worn frequently by her late mother-in-law, Diana, Princess of Wales.
Who was Princess Margaret?
Princess Margaret was the younger daughter of the late King George VI and the late Queen Elizabeth the Queen Mother.
She and her elder sister, Elizabeth, grew up in Windsor and were educated at home by their governess, Marion Crawford.
The princess' main interests within her public duties were welfare charities, music and ballet.
Margaret was also renowned for her glamorous lifestyle and reputed romances, including a proposal from Peter Townsend, who was a RAF officer in the royal household.
Attitudes to divorce in Britain at the time were still largely negative and Peter, who later divorced his wife, was considered an unsuitable match for Margaret, so the marriage did not go ahead.
In 1960, Margaret married photographer Antony Armstrong-Jones in 1960, who became the Earl of Snowdon. The couple had two children, David Armstong-Jones and Lady Sarah Chatto.
However, their marriage later broke down and they divorced in 1978.
Her health declined in the final years of her life, and Margaret passed away at the age of 71 in February 2022, after suffering her fourth stroke.