Royal cousins Zara Tindall and Prince William have been incredibly close from a young age, so much so that Princess Anne's daughter has become "the sister William never had", royal author Ingrid Seward tells HELLO!.
Born 13 months apart, the duo share a tight bond.
And Zara, 43, has come to the fore over the last few months, as a tower of strength for the royals during one of the most challenging times for the family.
© GettyShe has been visibly lending her support to her cousin William, most noticeably wrapping a comforting arm around him at Royal Ascot in June. And after embracing the future King, she then linked arms with him as they caught up in the Parade Ring.
"Zara is the sister William never had," Ingrid said in this week's issue. "They've always had terrific fun together and they've always supported each other."
© GettyWarm and affectionate, Zara, who is one of Prince George's godparents, has rallied to show her support to both William, whose wife Kate is undergoing treatment for cancer, and his father King Charles, who is recovering from cancer himself.
In May, along with Beatrice and Eugenie, Zara and her brother Peter Phillips, 46, helped William host a garden party at Buckingham Palace after he reached out to them on WhatsApp, leading one royal insider to say: "They are uniquely placed to understand how the royal family and the institution works, without having the titles and responsibilities themselves.
"They can support William as cousins because they've been there all his life and understand the institution."
© GettyZara's closeness to the monarchy and William was clear to see, as she chatted with his equerry Lieutenant Commander Rob Dixon and Kate's private secretary Lieutenant Colonel Tom White.
"She is very bright and intuitive about people," said Ingrid, author of My Mother and I: The Inside Story of The King and Our Late Queen. "And she has the best of both worlds. She understands what royal life is like, but she can live her life as she chooses, without the pressure faced by more senior royals."
Despite her support for the King and his heir, reports that accomplished horsewoman Zara might be called upon to take on royal duties or be given the title of Princess are very far wide of the mark, HELLO! understands.
"She can support her family and be invited to family occasions and other events, but also continue to live her life and do what she wants," says a friend. "The two things can co-exist. Why would she want to change that?"
To read the full article, pick up the latest issue of HELLO! on sale in the UK from Monday. You can subsribe to HELLO! to get the magazine delivered free to your door every week or purchase the digital edition online via our Apple or Google apps.
