In an interview at Balmoral, where the late monarch died on 8 September 2022, she says: "It was purely serendipity that I was there. I had been… two days up on the West Coast and I was coming back, stayed the night, was going south.
"We always enjoyed being at Balmoral. We spent a lot of time there in our youth and.. a lot of it was a probably more independent life than almost anywhere else. That's probably still true. That's a bonus."
Referring to the late Queen, she said: “I think there was a moment when she felt that it would be more difficult if she died at Balmoral. I think that we did try and persuade her that shouldn’t be part of the decision making process. So I hope she felt that was right in the end because I think we did.”
The Princess, who accompanied her mother’s coffin from Balmoral to London and then on to Windsor for a committal service at George’s Chapel, added: “When he takes the crown off the coffin, I rather weirdly felt a sense of relief. That’s it. Finished. That responsibility being moved on.”
Anne opens up in Charles III: The Coronation Year, which airs on Boxing Day.
She is seen making her own preparation for the ceremony at Westminster Abbey and later celebrating with her brother the King back at the Palace, where he kisses her hand.
Speaking about his new role as monarch, she says: "To be honest I’m not sure that anyone can really prepare themselves for that kind of change. At least not easily. And then the change happens and you go, Okay, I now have to get on with it.
"Monarchy is a 365-days a year occupation and it doesn’t stop because you change monarchs, for whatever reason. It’s a big operation. The amount of entertaining is much bigger than even they recognised.
“But I think, my brother, he is learning things about the organisation that he perhaps was very vaguely aware of before and he’s quite enjoying that too.”
The King himself is seen remembering his mother in emotional scenes after his horse Desert Hero wins the King George V Stakes at Royal Ascot.
“My late Mama won this race in 1955. She would be so thrilled,” he says.
Narrated by Helena Bonham Carter and directed by royal author and journalist Robert Hardman, the feature-length film also includes interviews with Archbishop of Canterbury Justin Welby, the Queen’s sister Annabel Elliot and her close friend and Companion of Honour Lady Lansdowne.
Charles III: The Coronation Year airs on Tuesday 26 December at 6.50pm BBC One & iPlayer
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