Prince Louis refused his father's hand as he began his school career with a settling-in day alongside brother, Prince George, and sister, Princess Charlotte.
The Duke and Duchess of Cambridge's youngest child appeared to be feeling confident as he approached Lambrook School in Berkshire, England, holding mother Kate Middleton's hand.
During the long walk, William could be seen stooping to offer a hand to the 4-year-old, who did not offer one back.
The future king then ruffled his son's hair, and Louis appeared to shake his head as he walked to meet his new headmaster.
Louis was wearing Lambrook School's uniform of a white, short-sleeved shirt, with blue shorts, socks and shoes.
William held daughter Princess Charlotte's hand, while Kate held Louis' on one side and Prince George's on the other.
A Kensington Palace statement on Wednesday read: "Ahead of their first day at Lambrook School, Prince George, Princess Charlotte and Prince Louis, accompanied by The Duke and Duchess of Cambridge, today attended a settling in afternoon for new pupils at the school.
"The settling-in afternoon is an annual event held to welcome new starters and their families to Lambrook and takes place the day before the start of the new school term."
George and Charlotte are also joining Lambrook School after the Cambridges moved out of London to new home, Adelaide Cottage, on the Windsor Castle estate in Berkshire.
Previously, they were at Thomas' Battersea, a fee-paying school in South London, around three miles from the Cambridges' old apartment at Kensington Palace.
The three royal children met their new headmaster, Jonathan Perry, who began by shaking William and Kate's hands Wednesday.
Kate could be heard saying, "Very nice to see you, Mr Perry, yes, hello. Thank you so much."
Perry then greeted the three royal children, by saying: "Welcome, George, welcome to Lambrook. Hello, Louis, welcome. And welcome, Charlotte, lovely to have you with us. We're very excited for the years ahead."
Kate hinted the family has looked around the school before when she said: "Lovely day again. Every time we turn up, it seems to be lovely weather."
Perry then asked the children whether they were excited and earned a chorus of positive responses. William said: "We're looking forward to it. Lots of questions, I think."
Perry replied: "Absolutely so. This is a great introduction to the school for you today so it's a pleasure to have you with us, so come on up."
As the family disappeared inside, Kate could be heard saying: "They do look very smart, I know."
In an August statement, Perry said: "We are delighted that Prince George, Princess Charlotte and Prince Louis will be joining us this coming September and very much look forward to welcoming the family, as well as all of our new pupils, to our school community."
The three royals will be back at school for the start of term Thursday.
Related Articles
Start your unlimited Newsweek trial