Princess Margaret's engagement to Antony Armstrong-Jones came as a shock to royal fans in 1960 since their relationship had remained private.
READ: Royals who married more than once: From Meghan Markle to Princess Anne
The couple met at a dinner party in 1958, but they didn't begin dating until the photographer was commissioned to photograph the royal – and his creative side came in handy when he designed Princess Margaret's unique ring two years later.
WATCH: Which royal has the most expensive engagement ring? Prices and meanings revealed
"Nobody knew about their relationship, there wasn't a whisper about it," Anne de Courcy, author of the biography Snowdon, told Town & Country. "She would see him in secret at his studio and yes, he would join her at parties, but no one could pinpoint which man she was interested in. The press focused more on the ones who were seen to be eligible. They didn't think of Tony who was often in the background."
Antony chose a very special ring for his future bride. Made up of a ruby surrounded by diamonds, the engagement ring reportedly resembled a rosebud as a sweet tribute to Princess Margaret's middle name, Rose.
Princess Margaret's ring was made of rubies and diamonds
Since then, Prince Andrew presented Sarah, Duchess of York with a Burmese ruby and diamond ring forming a flower pattern, which is similar to the engagement ring owned by her daughter, Princess Eugenie.
The Queen's sister hasn't shared many close-up photos of her special rock, but when the couple announced their engagement in 1960, they posed for a series of snaps inside the grounds of Royal Lodge - and it is just visible on her finger. The Windsor residence was formerly home to Princess Margaret and then-Princess Elizabeth, but it is now where Prince Andrew and his ex-wife Sarah live.
Sarah Ferguson and Princess Eugenie have similar flower-shaped rings
Margaret and Antony went on to get married at Westminster Abbey on 6 May 1960, just over two months after their engagement announcement. Their nuptials have gone down in history since it was the first royal wedding to be broadcast on television, with an estimated 300 million viewers tuning in.
READ: Lady Sarah Chatto looks stunning in unearthed wedding day photo
PHOTOS: Dapper royal grooms on their wedding days: Prince William, Prince Harry & more
Since then, most royal couples have followed suit, with the likes of Prince Charles and the late Princess of Wales, the Duke and Duchess of Cambridge, and the Duke and Duchess of Sussex's weddings also becoming momentous TV occasions.
The couple got married in 1960
The bride looked beautiful in a silk organza gown by Norman Hartnell that featured long sleeves and a full skirt using over 30 metres of fabric. She accessorised the gown with the Poltimore tiara and a cathedral-length veil.
Following their wedding, Princess Margaret and her husband welcomed two children together – David Armstrong-Jones and Lady Sarah Chatto.
However, the pair separated after 16 years of marriage and in 1978 they became the first royals to divorce since King Henry VIII in 1540.
RELATED: The real story of Princess Margaret's first love Peter Townsend
HELLO!'s selection is editorial and independently chosen – we only feature items our editors love and approve of. HELLO! may collect a share of sales or other compensation from the links on this page. To find out more visit our FAQ page.
Planning your wedding? Sign up to HELLO!'s brand new Bride Guide newsletter for expert advice, budget help, wedding inspiration and real life stories delivered straight to your inbox.