She was gracious in defeat as she accepted a huge wooden spoon for coming last in a sailing regatta against Prince William on Thursday.
Yet with a smile on her face – that only got wider when Princess Charlotte stuck a mischievous tongue out at the assembled crowds – the dressed-down Duchess of Cambridge has rarely looked more comfortable in her royal role as she did during the family day out on the Isle of Wight.
Holding her face in her hands during the comical prize giving, Kate, 37, appeared to take her team's defeat and disqualification in remarkably good spirits, shaking her head as compere Dan Snow joked: "This is the first time the Duchess has ever finished last at anything."
In fact, having once been dubbed 'Waity Kate' and depicted as a doormat during her decade-long courtship with the second-in-line to the throne, the Duchess is fast emerging as one of the Firm's most powerful players. As the wife and mother of a future king, Kate appears to have 'upped the ante' as she and William prepare to become the next Prince and Princess of Wales.
The King's Cup, a royal sailing tradition dating back to George V, was revived by the Cambridges to make money for their charities, including Kate's own causes Action on Addiction, Place2Be and the Anna Freud centre.
As with the Duchess's much-feted RHS Chelsea garden initiative, the once privacy-obsessed royal couple have been increasingly involving their children in their charitable endeavours.
Wearing nautical themed outfits, Charlotte, four, was joined by a gap-toothed Prince George, six, in Cowes as the Middleton grandparents joined in the seafaring. Sources close to the royal couple have told the Telegraph to expect more family-orientated engagements as the Cambridges prepare to 'transition' to the next level of their royal lives.
Having once faced cries of laziness for putting family matters ahead of full-time royal duty, with some below-stairs staff even nicknaming them the 'Can't-do-won't-do Cambridges', it seems the couple, and especially Kate, have a new-found sense of purpose.
"The work load, when analysed in terms of public appearances, is something that can be improved upon," says Joe Little, editor of Majesty magazine, "but the Cambridges are on a different level to where they were a couple of years ago."
Though Kate is "very, very conscious of being respectful," of the royal pecking order, according to one insider, "she's [also] conscious of being the next Princess of Wales, of course she is." And quietly keen to define her role as a future queen.
As another royal source put it: "For Princess Diana it was AIDS, for the Prince of Wales it's the environment – for the Duchess it's early years learning. There's a legacy point here. What's your legacy going to be? This is something she sees herself doing for the long-term because the problem requires that length of focus."
As with Heads Together, the royals' mental health campaign – which Kate has never got the credit for pioneering – she came up with the idea of focusing on children under the age of five after discovering many of the problems people encounter later in life stem from childhood.
She was particularly struck by research that suggested that pregnant women who suffered from depression could pass it on to their babies in the womb. John Lloyd, chairman of Action on Addiction describes the Duchess as a "committed" patron of the charity, where she is nicknamed 'two questions Kate' because she always asks a pertinent follow-up.
"She's been very good for us," says Lloyd. "She's helped to raise the profile even though she has had three babies in between."
The recruitment, two years ago, of Kate's private secretary, Catherine Quinn, previously the Chief Operating Officer and Associate Dean at Oxford University's Saïd Business School, has helped the Duchess to focus on 'quality rather than quantity' when it comes to carrying out royal engagements.
Quinn recently wrote to a lord-lieutenant, one of the Queen's representatives who oversee regional royal visits, informing him that the Duchess was being "increasingly selective in her engagements in a bid to balance her role as a high profile royal and mother of three children under six."
Operating "very much as a married couple" when it comes to diary planning, William and Kate both insist that they drive their children to school and nursery themselves; drop-offs and pick-ups are "sacred" time, and staff know it would have to be "a very high bar" to disturb it.
"She's a very hands-on mother," said one insider. "Things will get easier when Charlotte starts school in September because there will only be one drop-off, not two."
Politicians and other public figures are often in a hurry to invoke change, for fear of being out of the spotlight again once their five minutes of fame are up – but for the royals, it is very much a marathon not a sprint.
They also don't have the luxury of making mistakes, not least perfectionist Kate, who is under more pressure than most, thanks to her HM-like reputation for "never having put a foot wrong".
In a sign of her growing status within the royal family, Kate was given the Royal Family Order of Queen Elizabeth II in December 2017 – the Queen's highest personal honour.
Then in April she was made a Dame Grand Cross of the Royal Victorian Order (GCVO), the female equivalent of a knighthood, to mark her eighth wedding anniversary. "The Queen giving Kate the Royal Family Order is a very big deal," says Little. "Not everybody in the family gets it and they often have to wait a long time for it. Princess Michael of Kent never got it and is unlikely to get it.
The GCVO is for services to the sovereign so it is a sign of the high esteem in which Kate is held. "She's upped the ante, there's no doubt about it. Critics will say it's because of Meghan and due to the rivalry between the Cambridges and the Sussexes but I think it's more a case of William taking his job much more seriously now and so is she. "
"They are a Prince and Princess of Wales in waiting. She's more polished, more composed, more self assured in her public speaking. She's the real deal. And I'm not saying that to criticise the other Duchess."
Finding her purpose seems to have improved Kate's confidence when speaking in public, having started out in her royal life with a crippling fear of giving speeches. And although some have questioned whether early-years learning is an edgy enough cause to be championing – compared to Diana's AIDS and landmines quest – Kate hasn't held back.
Announcing that she was convening a task force to address early years learning in March 2018, she asked: "At what stage in a child's development could we, or should we, intervene, to break the inter-generational cycle of disadvantage? The more I have heard, the more I am convinced that the answer has to be: 'early' and 'the earlier, the better'. In fact, it would seem that we cannot intervene early enough."
Still, the Duchess was "endearingly nervous" when she was recently interviewed by Monty Don about the Back to Nature Garden she unveiled in July, according to one observer: "It was very striking. You get used to people in the public eye showboating and she's perceived to be perfect, but there's a vulnerability about her."
There's also a more mischievous side to her than the public might give her credit for (perhaps that's where Charlotte gets it from); the Duchess is described as having a "very dry" sense of humour and some "great banter", especially with her husband.
"The regatta played to the couple's competitive side but also the fact that they like to have a laugh together on jobs, when appropriate," said the insider. "They're in this for the long haul. The more they enjoy what they're doing, the better it is for everyone."