They said: “She can support her family and be invited to family occasions and other events, but also continue to live her life and do what she wants. The two things can co-exist. Why would she want to change that?”

The friend’s comments come after a source told the Express that Zara would not be able to join the Royal Family at Balmoral Castle because she had decided to enter the Wellington International Horse Trials.

The source said: “Charles really wants Zara and the family to join him on the last Sunday in August for the bank holiday service, but understands that her horse competitions are extremely important to her.

“Charles is hoping that they…will be able to come up the week earlier to muck in with the rest of the family so that everyone can enjoy the picnics and walks planned on the estate.

“Mia, Lena and Lucas get on amazingly well with George, Charlotte and Louis. There will be lots of children there this year so they are planning a mixture of adult and junior events to keep everyone entertained.”

The Wellington International Horse Trials are due to take place in Hampshire between August 24 and August 26.