Kate Middleton Stands with Queen Camilla at Solemn Remembrance Sunday Service

Chris Jackson/Getty Queen Camilla and Kate Middleton

Kate Middleton joined Queen Camilla at one of the most poignant events on the royal calendar.

Members of the royal family gathered in London at the Cenotaph war memorial for the National Service of Remembrance, also known as Remembrance Sunday. The annual ceremony, which always takes place the second weekend of November, honors those from the U.K. and Commonwealth nations who died in wars.

The Princess of Wales, 40, took her spot alongside Queen Camilla, 75, on the balcony of the Foreign and Commonwealth Office overlooking the service. Their husbands, Prince William and King Charles, laid wreaths at the memorial during the service, which also included a two-minute moment of silence at 11 a.m. local time.

Kate accessorized with a poppy pin, a symbol that has been used since 1921 to commemorate military members who lost their lives. She and other members of the royal family have been seen wearing the pins since the start of November. The royal opted to wear three poppies on her otherwise black ensemble. The symbolic flowers are believed to honor her great-grandmother Olive Middleton's three brothers, who all fought and died in World War 1.

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During her life, Queen Elizabeth was known to wear five poppies on her black coat during the Remembrance Sunday service. It's believed that her collection of flowers represented each of the services (Army, Navy, Air Force, Civil Defense), with the fifth representing women.

A wreath was laid on Queen Camilla's behalf by an equerry from the Royal Household for the first time. Her wreath featured the Queen Consort's racing colors, inherited from her grandfather, and echoed the wreath of the previous Queen Consort, Queen Elizabeth the Queen Mother. It also featured a handwritten card featuring Camilla's new cypher.

Chris Jackson/Getty Queen Camilla and Kate Middleton

The service at the Cenotaph was also attended by Prince Edward and Sophie, Countess of Wessex; Princess Anne and her husband, Vice Admiral Sir Tim Laurence; the Duke and Duchess of Gloucester; and the Duke of Kent.

While Princess Anne and Prince Edward also laid wreaths, Sophie stood with the Duke and Duchess of Gloucester from another balcony. On a third balcony were Sir Laurence and the Duke of Kent.

After all the poppy tributes had been laid at the Cenotaph, a short service of prayers and hymns was led by the Bishop of London. It ended with the national anthem, "God Save The King," sung by the veterans and members of the royal family. King Charles departed followed by his family, while up on the balcony Camilla and Kate made their exits, Kate stepping aside for the Queen Consort to precede her into the building.

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On Wednesday, Princess Kate shared a sweet moment with a 3-year-old boy named Akeem during her visit to Colham Manor Children's Centre. After Akeem showed interest in her poppy pin, she took it off of her jacket and gave it to him while sharing why she was wearing the accessory.

"Do you know what this is for?" Kate asked. "It's for remembering all the soldiers who died in the war. There you go — that's for you."

Mark Cuthbert/UK Press via Getty Kate Middleton

On Saturday evening, Kate and Camilla joined fellow members of the royal family at the Festival of Remembrance at Royal Albert Hall.

Kate opted for a black ensemble for the solemn event paired with some meaningful jewelry that previously belonged to her late grandmother-in-law Queen Elizabeth: the Bahrain pearl drop earrings and a four-strand pearl choker necklace with diamond piece in the center.

CHRIS RADBURN / POOL / AFP) (Photo by CHRIS RADBURN/POOL/AFP via Getty Images Kate Middleton and Prince William

In September, Kate chose the same pieces to wear for Queen Elizabeth's state funeral and committal service.