At face value, the latest official photograph is simply a delightful portrait of the Duke and Duchess of Cambridge looking forward to their first Mothering Sunday with Prince George.
Royal aides said the couple had decided now was a good time to let the public see how their son is growing up, aware of the intense interest in the future king's progress.
In truth, though, the picture has far greater significance. It has been timed to whet the appetite here and abroad for their tour of New Zealand and Australia, where Prince George will be the Royal family's not-so-secret weapon against republicanism when they arrive next week.
Anti-monarchist protesters may turn out, but their chants will be inaudible above the cooing of millions of parents whenever Prince George makes a public appearance. What must be striking terror into the republican movements of the two countries is the prospect of achingly cute pictures of the infant in the same frame as a wallaby, kangaroo or bilby. A single image of the baby prince with a koala could set their cause back 20 years.
Where China has panda diplomacy, Britain has Prince George diplomacy.
So it is hardly overstating the case to say that Prince George's public debut in New Zealand will be a moment in history, the first of many thousands of official engagements he will carry out during a life governed by duty.
At a personal level, it will also be a period of firsts for the Cambridges: their first time abroad as a family (the duke did not accompany his wife and son when they went to the Caribbean recently), the first time their son will mix with other babies, perhaps even the moment he takes his first steps.
As any parent knows, holidays or trips abroad are often the time when children reach landmarks in their development, and the Australian and New Zealand public (as well as royal watchers the world over) will be eager for any scrap of news.
It was in Australia that Prince William first began to crawl when he accompanied the Prince and Princess of Wales on a six-week trip in 1983, his own first foreign tour. In a letter to William's godmother, Lady Susan Hussey, the Prince of Wales wrote: "Today he actually crawled for the first time. We laughed and laughed with sheer hysterical pleasure and now we can't stop him crawling about everywhere." By the time the family got to Government House in Wellington, the Prince was telling friends that his son was crawling "at high speed knocking everything off the tables and causing unbelievable destruction."
Prince George will be nine months old before the end of the tour – the age his father was when he arrived in Australia in 1983.
There are already signs that Prince George is beating his father to key landmarks. At the beginning of March the Duchess of Cambridge told friends that Prince George had not yet started crawling or eating solids, but while the duke and duchess were on holiday in the Maldives a fortnight ago, he managed to move on all fours for the first time, a month earlier than his father.
By the time the couple attended a St Patrick's Day event in Aldershot on March 17, he was "crawling and eating" a lot, and had his first milk tooth coming through, they told soldiers from the 1st Bn Irish Guards.
The photograph released to Sunday newspapers in Britain also shows that Prince George has inherited his mother's brown eyes, although he has his father's fair hair and cherubic cheeks.
The first official photograph of the young prince since his christening in October was taken by Jason Bell, who also took the christening pictures. He stood in a private garden at Kensington Palace while the family, including their spaniel, Lupo, looked out of a ground-floor window in their new home, Apartment 1A.
The casually dressed couple posed with Prince George two weeks ago after they returned from their week's holiday in the Maldives. They would, no doubt, have noticed a difference in their son after a week away from him, but not as much of a difference as the rest of us can see in a baby who has grown considerably since we last saw him (as we can only see his top half, exactly how much will only become clear in New Zealand).
The next obvious milestone for Prince George would be taking his first steps. Although nine months is early for a child to start walking, it is not uncommon, and even the most die-hard republican Down Under would surely feel a twitch of pride if their future king learnt to walk on their home turf.
For the record, the most recent poll found that only 39% of Australians favour a republic, the lowest level for 20 years. In New Zealand, the figure is slightly higher, at around 41%, with a healthy majority still preferring the Queen as head of state.
But the former colonies are only a small part of the worldwide market for what could be described as Britain's strongest brand. Alongside the Queen and the Prince of Wales, the Duke and Duchess of Cambridge are among the most recognized people on Earth, which is why the Foreign and Commonwealth Office utilizes them so adeptly for soft diplomacy the world over.
The new photograph was released, royal aides said, to satisfy the anticipated clamour for fresh images in the build-up to the foreign tour; they insist it was not as a sop to British monarchists, who will have to wait their turn to see Prince George in the flesh. However, it will also appear in newspapers and on websites and television screens in scores of countries.
The Royal family know that when protecting their brand, less is more – hence the lengthy wait between the christening photographs and this single image. With the pictures and footage of Prince George that will emerge from New Zealand, it will help to project and strengthen the royal brand.
Max Foster, the London-based correspondent for CNN International, who will be covering the tour for the US-owned cable network, said: "The young royals are megastars everywhere, not just the UK. In fact, I'd say there's more adoration of them abroad, especially the US, but also some other places that might surprise you.
"There's huge interest in France and Germany, for example, and also in China and India. There's a particular fascination with George because he's the next generation and people haven't seen much of him. I'm constantly asked who he looks like. This new picture and the ones that come out of Australasia will be on the front pages, in every news stand, in every major city, before you know it, and they'll stay there for weeks."
The visit to Australia and New Zealand will inevitably prompt almost daily comparisons with Prince William's first tour 31 years ago. Far from being wary of comparisons with his own childhood, the Duke of Cambridge appears to be positively encouraging them.
In 1983, his first photocall during the tour was at Government House in Wellington, where he was staying with his parents and where the media were invited to take pictures of him playing on a rug in the garden with his parents.
On Wednesday, April 9 history will repeat itself when, at the same venue, Prince George makes his worldwide debut at a public engagement. All things being well, he will attend an event with his mother and father in Government House for Plunket Nurses and parents, where he will join other babies and toddlers. Plunket is New Zealand's largest provider of services to foster the health and development of children under five, with nine out of 10 babies in the country using its support.
The organization's Helen Clifton said: "We've got 10 parents that are delighted and humbled and excited about meeting Their Royal Highnesses and Prince George. They are families with children born within a week or two of the prince's birthday.
"The event will give them an opportunity to talk to parents in a relaxed and informal atmosphere about things that are going on with their children. At this age, some children are crawling and really motoring around. They can talk about what it's like to be a first-time parent.
"It will give the duke and duchess an authentic experience of what it is like to be part of a playgroup, which I don't think they would have had until now. It could even be Prince George's first playgroup?.?.?. I don't know."
Prince George will be given his own Plunket Well Child book and a blue cuddly bear as a gift.
Miss Clifton said: "We're hoping he has travelled well and is in a chipper mood. I think the team who will be involved on the day are very excited and probably slightly nervous about the prospect of hosting them. They have met a lot of parents and babies, but this is a globally recognized family."
Kensington Palace has been careful not to specify the other events Prince George is expected to attend, in case he is poorly on a given day, but the most likely place for him to appear in Australia is at Sydney's Taronga Zoo, where a bilby – a ground-dwelling nocturnal marsupial – has been named after him.
One place Prince George will not see is Ayers Rock, now known as Uluru, which his parents will visit while leaving him with his nanny overnight.
In 1983 Prince William had his own protection officer and chef, as well as his nanny, Barbara Barnes, and spent the first four weeks of the trip on a sheep station called Woomargama in New South Wales.
As in the case of Prince William 31 years ago, Prince George will travel with his parents, defying the royal tradition that no two direct heirs to the throne should travel together.
The Duke and Duchess of Cambridge have planned the entire tour around making sure they spend as much time as possible with their son; he will stay in three hub locations in Wellington, Sydney and Canberra while his parents make day trips further afield. As well as the Uluru trip, the duke and duchess will have one overnight stay in New Zealand away from their baby.
He will be looked after by his new nanny, Maria Teresa Turrion Borrallo, 43, a Norland College-trained Spaniard who began work at the beginning of March. Palace aides were irritated at erroneous reports that suggested the duchess's mother, Carole Middleton, would be going on the tour (it was never considered), although the couple will be placing a huge amount of trust in someone who will only have been in her job a month when the trip starts.
Huge crowds are expected to turn out to greet the family, particularly in the larger cities of Australia. Diana, Princess of Wales was overwhelmed by the adulation she received during her first tour there, telling the biographer Andrew Morton: "This was the real hard crunch, the hard end of being the Princess of Wales. There were thousands of press following us. We were away six weeks and?.?.?. the whole world was focusing on me every day.
"I went to my lady-in-waiting, cried my eyes out and said: ‘Anne, I've got to go home, I can't cope with this.'"
The Duchess of Cambridge, who toured Canada and the US in 2011, and the Far East in 2012, will have no such anxieties. Over the next week, she will be honing her travel wardrobe of more than 30 outfits, and ploughing through two lever-arch files of briefing documents on the 48 engagements she and the duke will undertake.
However, with Prince George by their side, the couple already know that the tour is guaranteed to be their biggest success yet.