“Expect Charlotte in a dainty coronet [small crown] – perhaps even the one the late Queen wore to her father’s coronation aged 10 – and the two brothers in frock coats and breeches,” historian Tessa Dunlop told the Mirror.

“Kate loves dressing up her children, so objections are unlikely. And the money shot everyone will want is a snap of the three siblings in their finery alongside the King and the Queen on Buckingham Palace balcony after the service.”

Just to show how special and how caring Charlotte is, Prince William and Princess Kate shared some of their children’s cards made for Mother’s Day from the previous years. The children, however, not only wrote cards for their mom but also for their late grandmother, Princess Diana.

“Dear Granny Diana, I am thinking of you on mother’s day,” Charlotte wrote in her card. “I love you very much. Papa is missing you. Lots of love, Charlotte”.

Meanwhile, George wrote: “Dear granny Diana, Happy happy Mother’s Day. I love you very much and think of you always, sending lots of love from George.”

Louis, who was just two at the time drew some animals which he stuck on the cards.

In the past, William opened up about his mother and revealed how he speaks genuinely of her in front of his children. “We’ve got more photos up around the house now of her, and we talk about her a bit and stuff. It’s hard because obviously, [Kate] didn’t know her, so she cannot really provide that level of detail,” he said in a 2017 BBC documentary.

“So, I do regularly, putting George or Charlotte to bed, talk about her and just try and remind them that there are two grandmothers, there were two grandmothers in their lives, and so it’s important that they know who she was and that she existed,” William added.

We are so glad the young royals get to hear of how special and how loved their late grandmother was.