Kate Middleton says she's happiest when she's with "my family outside in the countryside and we're all filthy dirty."

When it comes to her children, Kate Middleton wants them to remember the “simple things” in life.

In a rare interview with the Happy Mum, Happy Baby podcast, which premiered Saturday, the royal mom shared details of how she hopes her children, Prince George, Princess Charlotte and Prince Louis, will look back on their childhoods.

“Someone did ask me the other day, what would you want your children to remember about their childhood?” the mom of three, 38, told host Giovanna Fletcher. “And I thought that was a really good question, because actually if you really think about that, is it that I’m sitting down trying to do their maths and spelling homework over the weekend?”

“Or is it the fact that we’ve gone out and lit a bonfire and sat around trying to cook sausages that hasn’t worked because it’s too wet?” the Duchess of Cambridge continued.

Royal Christmas cards
Credit: Matt Porteous

She added, “That’s what I would want them to remember, those moments with me as a mother, but also the family going to the beach, getting soaking wet, filling our boots full of water, those are what I would want them to remember. Not a stressful household where you’re trying to do everything and not really succeeding at one thing.”

The Duchess of Cambridge, Giovanna Fletcher
Kate Middleton and Giovanna Fletcher
| Credit: Kensington Palace

Kate also reflected on her own memories as a child, growing up in the English countryside.

“I had a very happy childhood. It was great fun – I’m very lucky, I’ve come from a very strong family,” Kate said. “My parents were hugely dedicated to us – my siblings. I really appreciate now as a parent how much they sacrificed for us.”

The princess, who grew up alongside younger sister Pippa, 36, and younger brother James, 32, shared how supportive her parents, Carole and Michael Middleton, were as they attended every sporting event and spent every school break together.

The Middleton Family Release Images Of Kate Middleton
Credit: Getty

“They would come to every sports match – I was very keen on sport – they came to every sports match, they’d be the ones on the side-line shouting, and we’d always have our family holidays together,” she said.

“But I think the things that really resonate with me most are the simple things and actually I see that now with my own children, life now is so busy, so distracting and actually sometimes the simple things, like watching a fire on a really rainy day provides such enjoyment,” Kate continued.

Kate Middleton and Prince Louis
| Credit: Matt Porteous/PA
Credit: Matt Porteous/PA

“I remember that from my childhood – doing the simple things, going for a walk together, and that’s really what I try and do with my children as well because it totally strips away all the complications, all the pressures… as a parent and I think these experiences as well mean so much to children and the world that they’re in which is a real adventure for them at that age.”

With the conclusion of every episode of her podcast, Fletcher starts three sentences that the guest then finishes. When it came to the last one, the royal mom of three revealed a heartwarming detail of her family life.

“I’m happy when…” Fletcher started.

Kate replied, “I’m with my family outside in the countryside and we’re all filthy dirty.”

The Duke of Cambridge family
Prince William with Prince Louis, Princess Charlotte and Prince George
| Credit: Kensington Palace/Twitter

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Kate appeared on the podcast to promote her survey “5 Big Questions on the Under Fives” — which more than 200,000 people have taken part in.

The pair met in Birmingham as Kate’s survey kicked off last month. About a week later, Fletcher joined the Duchess of Cambridge at one of her outings to a nursery in Stockwell, London. The survey asks people “what is it that matters for them in raising their children today,” the royal mom explains in the podcast.

Prince William, 37, and Kate have had a whirlwind of a last month, from the royal mom traveling to the four corners of the U.K. to promote her new initiative for early childhood development to the couple joining Prince Charles and his wife Camilla, Duchess of Cornwall on a rare joint outing. But they are taking time off next week to spend time with their three kids during George and Charlotte’s school break.