Charles' touching hidden gesture for Kate at Trooping the Colour revealed

As they both simultaneously battle cancer, King Charles and Catherine, Princess of Wales have no doubt have something to bond over – a bond strong enough to break royal protocol, it seems.

In a move that we all seem to have missed, Charles broke his own rules out of affection for his daughter in law.

Kate made a triumphant return to the spotlight during Trooping the Colour, interestingly taking the place right next to the monarch as the family stood on the balcony.

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Last year the spot was occupied by Prince William, and is usually reserved for the next in line to the throne

Former royal butler Grant Harrold had some insight on the significance of the change.

He told OK! Magazine, "It is changing protocol to show the King and Kate united with each other and going through similar battles, so I would say this is down to the King's preference.

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Kate's public return as royals unite at Trooping the Colour

"The balcony [line-up] is orchestrated, so I have a feeling the King said to Kate, 'You stand next to me.'"

The move is also believed to be a sign of respect for Catherine, who chose Charles' official birthday celebrations to return to the public eye.

The shuffle seemed to have made the occasion more fun for the sovereign, with Kate making a mystery comment that made them both laugh.

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The father and daughter-in-law have had almost concurrent health battles.

Both were treated at the London Clinic in January, leading to the news of their diagnoses – Charles' in February and Kate's in March.

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