It was an almost imperceptible gesture, but one that spoke volumes.
As the Princess of Wales turned to leave the annual Service of Remembrance on Whitehall after making a poignant return to royal duties, the Duchess of Edinburgh, who had watched the emotional event firmly at her side, placed a reassuring hand on her back.
© GettyKate, who has been seen in public only a handful of times this year, had been determined to attend the important event, where her husband was laying a wreath, and Sophie had moved from her original position on another balcony to support her after the Queen pulled out for health reasons.
It was the latest demonstration of sisterly support between the two women, and one which revealed just how much the royals have wrapped a protective arm around stoic Kate during this most difficult of years.
"The royals have always shown a human side but there is more warmth now," royal author Ingrid Seward tells HELLO! "That gesture of Sophie putting her arm around Kate is something you wouldn't have seen a few years ago."
"That moment said a lot," agrees royal biographer Robert Jobson. "The royal family are all looking after Kate and there is a protective bubble around her."
As the royal women stood shoulder to shoulder on the balcony overlooking the Cenotaph, they chatted warmly to one another just as they have done so many times over the years at both public and private royal gatherings.
The close bond they have always shared seems only to have grown stronger since Kate revealed in March that she was being treated for cancer, which was discovered after major abdominal surgery in January. Like other family members, Sophie has been a tower of strength but, as a fellow mother who has faced her own health crisis in the past, she no doubt has a deeper understanding of the emotional toll the past few months have taken on Kate.
That, and the women's shared desire to protect their children will have brought them even closer of late, according to Ingrid, author of My Mother & I, the Inside Story of the King and Our Late Queen.
© Getty"They have a sisterly bond and Sophie is like the older sister Kate never had," says Ingrid.
"They are both incredibly kind girls and have a caring side to them. They are both protective of their children. Sophie has had a young family, so she knows what it's like trying to protect them while being in the royal world.
"Sophie also has experience of life-threatening illness - she nearly died when her daughter Louise was born. She has been there in the background, as part of a private support network.
© Getty"They have a huge amount in common having probably formed a bond very much at the beginning," she continues. "Sophie was there for Kate in an unofficial capacity because she had the same experience of being a commoner marrying into the family.
"They both had really long romances with their husbands-to-be and Sophie lived at the Palace. By the time they got married they had more knowledge than the royal brides before them about what they were getting into."
"In terms of marrying into the family, they share that experience," royal author Robert Hardman tells HELLO! "They are both people who weren't in the royal orbit before and had to adjust to that.
© Getty"The Duchess is not that far ahead in her motherhood journey – her son is still at school. And the two families now live close to one another."
While the Princess is mother to Prince George, 11, Princess Charlotte, nine, and six-year-old Prince Louis, the Duchess's daughter Lady Louise has just turned 21, while her son James, Earl of Wessex, is 16.
Since 2022, the Wales family has lived at Adelaide Cottage, in the grounds of Windsor Castle, just 11 miles from the Edinburghs' home Bagshot Park.
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