The Duke and Duchess of Cambridge often share insights into their family life with their children, including their favourite hobbies.
The conversation was released by Kensington Palace on Thursday, but was recorded in autumn 2020, when Louis was two.
WATCH: Kate Middleton says she can't keep up with Prince Louis
The Duchess told the little girl: "Louis has got so big now, he's very quick running around and he's on his little scooter as well. He's very quick. I can't keep up with him."
Last month, Prince Louis celebrated two milestones – his third birthday coincided with his first day at Willcocks Nursery School in Kensington.
And it seems the little boy is full of energy, as the photo shared by the Duke and Duchess showed Louis proudly beaming on a balance bike.
Louis kept mum Kate on her toes at the polo in 2019
When Louis was just a year old, mum Kate had her hands full as she was pictured chasing after her son during a polo match in summer 2019.
The Cambridges also celebrated Princess Charlotte's sixth birthday last weekend, with Prince William revealing during his visit to the West Midlands on Tuesday how the family had marked his daughter's special day.
William, 38, was talking to Jenna Jackson, the company's lead HR business partner and a mother-of-two, who asked him if Charlotte had enjoyed her birthday.
The Cambridges pictured in December 2020
"She had a lovely day, thank you," said William. "Last year it was her birthday in lockdown but this year we were able to have one other family over."
The Duke also revealed Charlotte's hilarious response when anyone asks her age.
He was heard joking in a video shared by MailOnline: "If you ask her, she says she's 16."
He added: "Charlotte says, 'I'm six now, I'll do what I do want.' They grow up very fast."
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