Prince William used to "get the giggles" during the royal family's annual Christmas church service.
Prince William joins his family at church every Christmas
The British royals traditionally spend the festive season at Queen Elizabeth's Sandringham Estate and many well-wishers turn out on 25 December to watch the family walk to nearby St. Mary Magdalene Church, and the 39-year-old royal has fond memories of getting distracted during the sermon by his cousins when he was younger.
Explaining how the pews inside face one another, William said: "And what's very good about it is that we sit opposite each other as a family, and growing up, having my cousins sat opposite me has always been quite difficult to keep a straight face at times.
"I have had the giggles many, many times in the service. Luckily, no one's filming it. So you can get away with it, and on Christmas Day, it's fun to have a giggle and enjoy yourself."
William finds the walk from Sandringham House to the church "very soothing".
Speaking on Apple Fitness+'s 'Time to Walk' series, William - whose walk took him through the Sandringham estate, past the church and eventually to Anmer, where he and wife Catherine, Duchess of Cambridge, have a home - said: "My family spend their Christmases in Norfolk at Sandringham, which is in the UK. Walking along here, you've got big pine trees that are quite synonymous with this part of Norfolk. And I love the smell of pine in the winter. It's very soothing.
"As we're walking along here, it's been a walk that my family have done for many, many years on the way to church on Christmas Day. It must be at least 25 years by now."
And the stroll reminds William of his late grandfather, Prince Philip, who died in April aged 99.
He said: "I have strong memories of walking down here, and my grandfather, he used to walk so fast that there'd be huge gaps and spaces between all of us walking down, and there'd be us at the back with little legs trying to keep up.
"You know, I think, over time, you start to feel quite attached to those moments and those memories before."
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