The late Queen Elizabeth II reportedly broke one major royal tradition for Carole and Michael Middleton. It has been reported that Princess Catherine’s parents were invited to stay at Balmoral Castle during a previous visit to Scotland – instead of staying in one of the other homes on the estate – in September 2016.

Upon the late Queen’s request, Carole and Michael had been travelling to Scotland to spend time with William and Catherine, as well as their grandchildren, Prince George and Princess Charlotte, then aged three and one.

A source told the Daily Mail’s editor-at-large, Richard Kay that the decision was “William’s idea”.

The source said: “[William] very much wanted his grandmother to make them especially welcome. They were at the top of a very long guest list.”

William has had a longstanding close bond with his in-laws, especially his mother-in-law.

Former royal butler Grant Harold has previously discussed the warm bond between William and the Middleton family.

Speaking on behalf of Heart Bingo Online, Mr Harrold previously said: “William always had a good relationship with both Kate’s parents, but especially her mother, Carole.

“When I was working with the family, he used to go and spend weekends at their house, which I know he really enjoyed.”

Sources also discussed how much the Middletons welcomed William into their family, sharing: “They are a warm and welcoming family, and I imagine gave him some of the normality he craved during his 20s and 30s.”