The Duchess of Cambridge hinted that Prince George could be a future Wimbledon star when she revealed that he has a racket and is already playing tennis.
Kate also said she plays tennis with William - but he is "frustrating" to play against as he is left-handed.
The Duchess met players, ball boys and girls and members of the armed and emergency services as she arrived at Wimbledon for ladies' semi-finals day.
She was greeted by the chairman of the All England Club, Philip Brook, at the players' entrance, before being introduced to staff and officials on the players' lawn.
She told Briton Greg Rusedski, who is here in the men's invitational doubles, that George has already taken an interest in the game, despite being just two years old.
Rusedski said after meeting her: "She talked about George, her little boy, playing tennis."
Asked what she said, Rusedski said: "He's got a racket and he enjoys playing tennis, and obviously she plays with William...
"So they obviously enjoy the sport very much."
Rusedski, the former British number one, said Kate did not say anything about how the young prince is shaping up as a player, but he added: "As long as he is enjoying it at this age that's all that matters, really.
"It's too young to know what's going to happen for the future, but it's one of those sports for life.
"She was very friendly. I think everyone was delighted to meet her today at Wimbledon and she's obviously a great ambassador for the country."
The Duchess also had a word of encouragement for Andy Murray's coach, Ivan Lendl.
Lendl said Kate apologised for not having seen any of Murray's Wimbledon matches so far, but asked him to pass on a message to the Scot, saying: "She said to wish him the best."
And Lendl said Murray's quarter-final against Jo-Wilfried Tsonga on Wednesday was "the best I have seen Tsonga play".
The Duchess chatted with four ball boys and ball girls who have been on duty during the Championships.
The youngsters were not told who they were going to be meeting as they lined up smartly on the lawn, and when Kate arrived they broke out into nervous smiles.
But she soon had them grinning and put them at ease as she asked them how their tournament had gone.
Wearing a canary yellow, wool crepe dress by Roksanda Ilincic which she first wore on a tour of Australia in 2014, the Duchess also chatted with wheelchair players Gordon Reid and Louise Hunt, who are playing in the inaugural wheelchair singles event at Wimbledon.
Kate questioned Reid about his preparations for the tournament, asking him if he prefers grass or other surfaces, and told him it was "really great, amazing" that the singles event is now in the Championships.
And when Reid told her he was a left-hander, she said: "My husband is left-handed as well. It's so frustrating playing him."
The Duchess also chatted with Todd Woodbridge, who won nine Wimbledon doubles titles, and told Venus and Serena Williams's mother Oracene Price - who was wearing ripped jeans and a cardigan - that she was looking forward to watching the two women in action on Centre Court.
Catherine said: "I'm looking forward to it, good luck both of them, very good luck."
Before making her way to the Royal Box, Kate met Major Alan McTaggart, who is working at his fifth Championships and is the officer in charge of the 350 staff at this year's Wimbledon.
She also met RAF Warrant Officer Class One David Knights, the service stewards office manager, and Chief Petty Officer Angie Whitehorn, who has served in the Navy for 27 years and is working at her seventh Championships.
The Duchess was also introduced to Detective Chief Superintendent Stuart Macleod, who has planned the police operations at Wimbledon and retires on the last day of the tournament, and fire crew manager Lucia Mancuso, from Battersea fire station, who is the head of fire patrol at the Championships.
The ball boys and girls were all smiles after meeting the Duchess.
Dominic Barnaby, 17, from Crystal Palace, said: "It was quite nerve-wracking. I looked to my right and saw her walk through the door and my hands started sweating quite a bit.
"It was surreal - it is not something that happens every day."
Olivia Mellett, 17, from Surbiton, said Kate asked about their training and the discipline involved.
The teenager, working at her fourth Wimbledon, said she "felt my heart racing" when the royal visitor arrived, and that the Duchess had quizzed them on how they learn to roll the ball so smoothly on court.
She added that meeting Kate was "brilliant - it was so good".
Anissa Mayouf, from Merton, said the Duchess suggested it might be intimidating to go on court for the first time.
The 14-year-old added: "I would have to agree with her because there are lots of people watching us, there are crowds there and you have to try and do your best for the players."
And Portuguese ball boy Tomas Morais, 14, from Putney, said Kate told him she thought they were all doing a "great job".
He described the Championships as "probably the best two weeks of my life".
The Duchess later watched Serena Williams demolish Elena Vesnina in two sets, before her sister Venus took on Angelique Kerber in the other ladies' singles semi-final.
Bee Gee Barry Gibb - who evoked memories of his 1970s disco heyday in a shiny blue and black jacket and sparkling black trousers - Downton Abbey actress Dame Maggie Smith, and Sophie Turner, who stars in Game Of Thrones as Sansa Stark, were also guests at the All England Club.