Mike and Zara Tindall may have to decline special King Charles invite in royal diary clash

Mike and Zara Tindall have been invited to join the Royal Family at Balmoral this summer, but their attendance is in doubt after the King's favourite niece has entered the Wellington International Horse Trials at the same time, Express.co.uk has learned.

An extremely well-placed source has revealed that Zara has submitted an application to compete at the event which takes place on August 24 to 26 in Hampshire.

The Royal Family are planning their annual Sunday service 535 miles away at Crathie Kirk church near Balmoral in Scotland on the same bank holiday weekend.

The source adds that King Charles is so determined to have Mike, Zara and their three children join the family that he's considering moving the church service forward a week to accommodate the Tindalls.

"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," said the source.

"Charles is hoping that they [the Tindalls] 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."

Express.co.uk revealed earlier this month that the Duke and Duchess of Sussex have not been invited to Balmoral to join the rest of the Royal Family because King Charles, 75, and Queen Camilla, 77, want to relax and unwind.

"Harry and Meghan will not be joining the rest of the Royal Family in August," said the source.

"The King is keen for it to be a happy family occasion which will see members of the Royal Family come together for just over a week to discuss plans for the future and to unwind."