Daniela Elser: Powerful detail in new Kate Middleton photo

The Duke and Duchess of Cambridge attended Royal Ascot on Friday for the fourth day of this year's horse racing event. Video / AP / Getty

OPINION:

A rare new image of the Duchess of Cambridge has exposed a very powerful alliance forming inside the royal household.

Just call it the Dawn of the Day of the Double Duchess.

On Tuesday, the UK's pre-eminent source on composting and conservatory renovations, Country Life magazine, revealed the cover of their latest issue, an edition guest-edited by none other than future Queen and eternal wellie-wearer Camilla, Duchess of Cornwall.

Kate photographing Camilla for the cover of Country Life magazine. Photo / Twitter

Sporting a blue dress and cardigan and sitting on a wooden bench, her makeup nearly non-existent, Camilla looks happy as a Cornish clam to be pottering about her garden and not having to entertain an Azerbaijani cultural delegation or retrieving a priceless diamond earring out of a Jack Russell's mouth.

But news.com.au does not really if ever, cover Camilla because well … not that many people besides me are really that interested in her.

No – why the Duchess' cover picture is worth talking about today isn't because of what the image shows, but who took it.

Enter Duchess number two, Kate, Duchess of Cambridge.

At the same time Country Life revealed its cover, the magazine also released a behind-the-scenes image of the photo shoot, showing Camilla posing in the garden of her private Wiltshire home Ray Mill House with Kate in snapper mode.

A behind-the-scenes image of Kate photographing Camilla for the cover of Country Life magazine. Photo / Twitter

As the magazine's editor Mark Hedges told the Telegraph when discussing the shoot with Camilla: "She immediately replied, 'Oh I'd quite like Catherine to do it.'

"I spent the next three or four minutes desperately racking my brains trying to think of a professional photographer called Catherine.

"Then I suddenly grasped what she meant – one of the most amazing things that could happen.

"I don't think anyone else would have made her feel so relaxed.

"They didn't bother too much with hair and make-up, they just got some flowers from the garden and got on with it."

The picture which Kate took for the Country Life cover. Photo / The Duchess of Cambridge

On paper, the two women don't have much in common besides both having caught the eyes of future kings.

Camilla's life, pre-royal marriage, was like a poster for a certain sort of bucolic upper-crust existence, a horsey whirl of muddy breeches and dinners cooked in the Aga.

Kate, for her part, came from a good stolid background, had a university degree, a couple of part-time jobs and seemed to enjoy nothing more than endlessly haunting the mid-priced boutiques of Chelsea with her sister Pippa, the odd Mayfair nightclub occasionally getting a look-in too.

While Camilla was seen lunching with Kate ahead of the latter's wedding in 2011, giving her a spot of friendly advice, they never appeared particularly close. Kate has probably never spent an hour puzzling over how to get rid of rose blight or what to do with a lame mare and Camilla has likely never entered a Zara outpost in her life or spent summer in Mustique.

But something in the last little while has very clearly shifted on this front and somehow Camilla and Kate have become a formidable – and very friendly – power couple.

Most obviously, they seem to really get on like a house on fire.

In February, Charles, Camilla and the Cambridges' undertook a highly unusual joint engagement to visit a project run by the Prince's Trust. Cue lots of big, chummy smiles.

Camilla and Kate have become a 'formidable power couple'. Photo / Getty Images

During Trooping the Colour, Camilla and Kate shared a carriage, waving to the crowds as a double-act.

There the two duchesses were at the Order of the Garter ceremony in Windsor last month, getting on like a grade-II listed house on fire during the carriage procession.

What makes this new-found, or at least newly revealed, a bond so remarkable is not that they seem so pally (though I would like to imagine they spend the occasional Friday night a deux with a jug of Harvey Wallbangers watching Love Island) but what an abject departure this is in royal history.

In every photo of the previous two women to marry into the house of Windsor, the Queen Mother and Queen Mary of Teck, they eternally look miserable to be in such proximity. (Want to know what sort of person Mary was? She sent her four-year-old epileptic son Prince John away from her to live with his nanny and he died in her Norfolk cottage at age 13.)

The point is, never before have we seen an alliance quite like this of Kate and Camilla, two women who grew up sans titles and noble lineages and yet in whose hands now rests the future of the monarchy.

And thank god for that.

Camilla and Kate sat side-by-side during the Trooping the Colour parade in June. Photo / Getty Images

When the sad but inevitable comes when the Queen passes away, the coronation of Queen Camilla and later the arrival of the new Princess of Wales will represent a new era where the two most powerful women in the monarchy are closely aligned.

Having a Queenly coalition not only willing but happy to work in step will have implications for The Firm as a family and as an institution.

Unmistakably, after years of the words 'rift' and 'feud' appearing in royal headlines with grinding ubiquity, some lovely unity and harmony will be just the ticket. Imagine: A royal family that actually likes one another. Quite the PR palate cleanser.

Then, on a practical level, a royal house that can work as a cohesive, functioning business will quite simply do a better job. If clashing egos, agendas, schedules and causes can be minimised and the whole thing is just a better-oiled and more rationally functioning beast, then it will only benefit the institution.

The touchy-feely royal news does not stop there today though.

On Tuesday in London, Kate, in her guise as the Patron of the All England Lawn Tennis and Croquet Club which runs Wimbledon, was back on the job which seems to largely consist of wearing sundresses and clapping enthusiastically.

Notably, she did make her debut outing for this year's tournament alone as she often does.

What would better set off a $2665 ($2938) Alessandra Rich dress, which vaguely resembled something one might have bought for a tenner from the Dynasty wardrobe sale, and pearl earrings than her husband by her side?

There William was alongside Kate, first in the royal box watching Novak Djokovic play a quarter-final match before switching courts to watch British player Cameron Norrie make it through to the next round.

Interesting. Very interesting.

Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge in front of the Eiffel tower. Photo / Getty Images

See, while William does usually attend the tournament with Kate, for at least the last four years he has only trotted along for the finals and yet here he was a good five days early.

Then there is what the Cambridge duo got up to during their day out. They giggled, smiled adoringly at one another and bantered. In fact, the pair looked more like newly enamoured lovebirds who had just met on some dating app for European royalty (Monarchy Match?) than a couple who have been married for 11 years, have a horde of staff, three children, soon to be three homes, two royal foundations and one dog to their names.

Look, it's all really lovely and all just so … unexpected.

For yonks when they were out in public the Cambridges adopted a far more reserved attitude to one another, as if they were practising a certain marital social distancing years before it came into vogue.

But in the last few months the pair have laughed, joked and been tactile in a way that is a lovely break from their former quasi-Mormon MO.

Maybe this could have something to do with the fact that the years of sleepless nights, feedings, nappies, and that seemingly never-ending series of scandals and family crises are, at least for now, behind them.

Still, in the same way as Kate's down-low partnership with Camilla, this new warm'n'fuzzy phase is only good news for anyone with any sort of vested interest in the future of the whole monarchy business.

Whoever thought the house of Windsor would end up in such good hands? Especially one set with plenty of dirt under the nails?

Daniela Elser is a royal expert and a writer with more than 15 years' experience working with a number of Australia's leading media titles.