Kate has opened up about 'competitive' rivalry between George, Charlotte and Louis

Prince William and Kate Middleton have often opened up about what their lives are like behind closed doors, and royal fans are particularly fond of sweet anecdotes about their three children, Prince George, Princess Charlotte and Prince Louis. 

While Louis has charmed the nation over the last year with his cheeky public appearances, Charlotte is said to have a sassy character and George is reportedly already preparing for his future role as King.

And it seems that the Prince and Princess of Wales are keen to encourage George, Charlotte and Louis to take part in various sports - and their competitiveness is something that Princess Anne has commented on recently.

William and Kate joined former England rugby player Mike Tindall for an episode of his podcast, The Good, The Bad and The Rugby. 

Mike, who married the late Queen Elizabeth II's granddaughter Zara in 2011, was also joined by his mother-in-law, Princess Anne. 

During the special episode, the royals discussed the importance of sports as well as competitive spirit - with Mike even going on to compare William and Kate to Monica from Friends. 

Kate responded: "I'm really not that competitive, I don't know where this has come from!"

However, she went on to say that she has never been able to complete a tennis game with her husband as 'it becomes a mental challenge between the two of us'. 

When asked if the Wales' three children have a competitive streak, Princess Anne was quick to add: "Just a little bit, I would suggest!"

Kate continued: "What's interesting is that they all obviously [have] very different temperaments.

"And as they're growing and trying out different sports - they're obviously still really young - it's going be interesting to see how that grows and develops."

We'll have to wait and see!