Prince George and Prince Louis love playing rugby.
Catherine, Duchess of Cambridge, was recently named as the new patron of English rugby, replacing Prince Harry in the role, and she's revealed her two sons, who are aged eight and three respectively, are already big fans of the sport, though she's worried about her youngest boy's "kamikaze" approach to physical activity.
Speaking about her boys and their passion for rugby, the duchess shared: "They're all enjoying it. Louis is kamikaze, we're worrying about when he gets older, he'll be in the middle of everything."
Catherine - who also has Princess Charlotte, six, with Prince William - told how her kids play both netball and rugby at school and she loves to see gender lines getting broken down.
During a chat with the England's women squad, she said: "Now that there is a move towards co-ed sport, so it's not just girls playing netball, but other sports like rugby, which is great."
The duchess joined the men's and women's teams for training exercises on the pitch at Twickenham on Wednesday to mark her new patronage and she's looking forward to learning more about the game.
After being presented with junior England kits for her children, she said: "I'm very proud to be here. I've got lots to learn, I've been looking at different players and tactics."
The duchess was named as the new patron of the Rugby Football League and the Rugby Football Union earlier this week.
The appointment puts her in direct competition with her husband, who is the patron of the Welsh Rugby Union.
She said on Twitter: "I am so thrilled to become Patron of the @TheRFL and @EnglandRugby [England flag and rugby ball emojis] Two fantastic organisations who are committed to harnessing the power that sport can have in bringing communities together and helping individuals flourish.
"I look forward to working with them across all levels of the games, and to cheering England on in what promises to be an exciting year for both sports! C (sic)"
Her appointment has also been welcomed by Ralph Rimmer, the chief executive of the Rugby Football League.
He said: "We are truly honoured by the appointment of the Duchess of Cambridge as the Rugby Football League's Royal Patron. We are delighted to welcome her as we prepare to host Men's, Women's, Wheelchair and Physical Disability Rugby League World Cups in England this autumn."
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