Queen Elizabeth II was stunning at Princess Margaret’s royal wedding.

A photo of the Queen taken during her sister’s royal wedding resurfaced on Instagram. In the snap, Her Majesty looks stunning in her turquoise blue gown. The Queen sits alone, holding her hand while looking away from the camera.

The monarch is very glamorous in every inch in her matching gown and hat. Queen Elizabeth II’s outfit at Princess Margaret and Anthony Armstrong-Jones’ big day in 1960 was designed by Norman Hartnell, the royal couturier extraordinaire.

The full-length gown uses a simple turquoise blue silk taffeta and silk tulle with guipure lace on the top and down the back. The lace also adorns its matching bolero jacket. Meanwhile, the Queen’s hat was topped by roses as a nod to Princess Margaret Rose.

Queen Elizabeth II paired her outfit with two large strands of pears, a large version of her pearl and diamond button earrings, and a bracelet and watch. She also accessorized with the True Lover’s Knot Brooch.

Princess Margaret’s wedding was the last occasion where royal women would wear long day dresses. Even then, it was still slightly less formal compared to Queen Elizabeth II’s own wedding in 1947 where the women wore order sashes.

Princess Margaret and Prince Philip once had a disagreement over Armstrong-Jones. The Queen’s sister was reportedly “ill with rage” after she learned that the Duke of Edinburgh blocked her husband from becoming Lord Snowdon in 1961. Armstrong-Jones still received the peerage in October of the same year.

Prior to marrying Armstrong-Jones, Princess Margaret planned to tie the knot with Peter Townsend. Unfortunately, he had been divorced and the Queen couldn’t give her consent to them.

Princess Margaret was forced to choose her duty to the Commonwealth over her heart. Townsend was exiled and wasn’t permitted to return to Great Britain for years, which was difficult for him as he had been serving the country for years.

For Townsend, he received many medals for his service but he and Princess Margaret didn’t receive any for their sacrifice. He felt that falling in love with the Queen’s sister and being loved in return was the worst crime he did.

“Margaret lost a true love. I lost not only that - but my great love for my country as well,” Townsend said.

Queen Elizabeth II
Queen Elizabeth II is seen at the Chichester Theatre while visiting West Sussex on Nov. 30, 2017, in Chichester, United Kingdom. Getty Images/Stuart C. Wilson