Judy Murray said she warned the Duke and Duchess of Cambridge off any plan to make Prince George "the next Andy Murray" as she accepted an OBE.
The Scottish tennis coach and mother of Britain's most successful modern player told William it was a "very difficult journey" as he presented her with the honour at Buckingham Palace on Friday.
Last month Kate revealed during a visit to the Lawn Tennis Association's headquarters that she was teaching the game to the four-year-old prince but he "only wants to whack the ball".
-- Kensington Palace (@KensingtonRoyal) October 31, 2017
Ms Murray, speaking after Friday's ceremony, said: "He (William) was saying about Prince George, Catherine trying to teach Prince George how to play tennis and how I think she had said last week that she wants him to be the next Andy Murray.
"I'm sure she was joking. I was trying to put them off that - I said it's a very difficult journey."
Ms Murray, the former Great Britain Fed Cup coach, received her OBE for services to tennis, women in sport, and charity. She trained her two Wimbledon-winning son, Andy and Jamie, as children.
Two-time SW19 singles champion Sir Andy recently became a father again himself after wife Kim Sears gave birth to their second daughter - their first, named Sophia, was born in February 2016.
Ms Murray spoke about her forthcoming appearance in the Strictly Come Dancing Christmas special, where she will perform the Charleston with professional partner Neil Jones.
She said: "When I did the Charleston with Anton (Du Beke) three years ago, (judge) Craig Revel Horwood said to me 'Not an ounce of swivel, darling', so my goal is to show him I can swivel."
Rehearsals have already started for the BBC show, with Ms Murray saying her first experience of taking to the dancefloor gave her "a lot of confidence".
She said her appearance in 2014 led to more interest in her work, training female tennis coaches.
Ms Murray, who has campaigned for gender equality in sport, added that the quality of women's games was encouraging girls to get active.
"Now, I think, with the success of England women winning the cricket, for example, the rugby, the football, the hockey, the netball, they are watchable because the performances are so good.
"So TV will want to cover them, more people will watch and that will get more people into sports. So it's that whole thing of 'If you can see it, you can be it'."