Royal fans were taken by surprise when Prince George and Princess Charlotte made an appearance at Prince Philip's memorial service.
It was known well in advance that their parents the Duke and Duchess of Cambridge would be attending - but there had been no word their two oldest children would be there until just before the event.
It is the most high-profile royal event by far that the two youngsters have attended with William and Kate keen to give them and younger brother Prince Louis as normal an upbringing as possible.
Body language expert Judi James told OK: "You could tell from the way George copied his father totally that there had been some rehearsals and training behind the scenes.”
This means that their public appearances have so far been few and far between.
However, now they are getting older, there have been signs both youngsters - and especially future king Prince George - are now being primed for royal life.
Slow introduction
Rather than have their children make appearances at many royal events, William and Kate have carefully selected the engagements to take their children to.
When they were much younger, the Cambridge youngsters were only really seen on the balcony at Trooping the Colour.
George and Charlotte have accompanied their parents on several royal tour - but again their appearances were limited.
It's only been in recent months that oldest child George has been seen more regularly - he went to the Euro final last July and the England v Wales Six Nations match last month.
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Speaking last year, Sunday Times Royal Editor Roya Nikkhah explained George's trip to the football was a "clever way" of showing him public life.
She told True Royalty TV’s The Royal Beat: "It was a very clever way of introducing him to public duties at such a young age because this is an official duty for Prince George.
"It's lovely and happy and there's a lot of emotion. Getting him used to big crowds and knowing that he is being watched by millions of people - it's quite a clever way of doing it.”
Learning of his role
But even though we've been seeing them more and more, it was only around two years ago that Prince George had it explained to him what his future would hold, according to a book.
In his book Battle of Brothers, royal author Robert Lacey describes how protective dad William wanted George to have a more normal life for as long as possible and always intended to break the news to his son gradually to give him "the precious gift of normality."
Lacey writes: "From George's earliest days, William made no secret of his wish to spare his firstborn the casual initiation - or non-initiation - that he felt he had suffered as a child."
Although William has not explicitly stated when he told his son he was an heir to the throne, but it's thought the conversation was had "sometime around the boy's seventh birthday" in summer 2020.
Lacey writes: "William's aim as a father, the prince stressed, was to give his son a 'normal family upbringing' enabling the monarchy to 'stay relevant and keep up with modern times'."
Rehearsing events
Meanwhile, at yesterday's event many were blown away by George and Charlotte's impeccable behaviour and said they took their cues from their parents.
And according to body language expert Judi James, the children’s remarkably composed, mature appearance was in fact the result of rehearsals.
Speaking to OK!, she explained: “William’s hand barely left his son’s shoulder and he used several pat-rituals as a tie-sign to register encouragement and approval.
"You could tell from the way George copied his father totally that there had been some rehearsals and training behind the scenes.”
Judi also noted that William and Kate often appeared as proud parents, helping out their children.
She added: "They were appearing here as proud and loving parents, gently continuing George and Charlotte’s induction into formal royal life."
Gentle reassurance
And another way that William and Kate have been helping to prep their children for their future roles is through gentle reassurance.
As they entered the Abbey yesterday, the eight-year-old future king and his six-year-old sister looked slightly nervous when they got out of the car and walked towards the building, however some reassuring words from mum Kate saw Charlotte start smiling.
According to lip reader Jacqui Press, Kate whispered to a very serious and nervous looking Charlotte, "you can smile", reports MailOnline.
Meanwhile, William held George's hand and gave him some instructions, saying: "Let's go in". He then guided his son towards the dignitaries and introduced them.
The youngsters shook hands with the clergy who bent down to speak to them, with Charlotte giving a large grin.
