JANE FRYER: Are Charles and Camilla brave enough to do Downward Dog with the yoga ambassador? 

What a truly spectacular morning in the ancient forest of The Hermitage in Dunkeld, Scotland. The River Braan roars by, full of meltwater from the Cairngorms. The giant Scots pines sway and sigh above. The air is thick with the tang of wet bracken and moss. Chunks of ice melt in the thin winter sun.

And there, on a giant rock beside the river, is Finlay Wilson, yogic ambassador to King Charles’s Prince’s Foundation, stripped to the very honed waist and performing a series of advanced yoga poses, in a kilt.

First, he does Warrior I: legs spread, muscular arms stretched upward, soft swirls of strawberry blond chest hair gleaming and giant calves bobbing and flexing as he holds the position, deeper and deeper.

Then he does Wild Thing: a very bendy back bend with one arm outstretched that, well, does rather make my heart sing.

And finally Bird of Paradise, where he bends his left leg, tucks it over his left arm, swivels slightly and stretches it up behind him. Which is quite something to behold when performed in a kilt, worn in the full Scottish tradition.

No wonder the first luxury yoga and wellness retreat at King Charles’s Dumfries House in East Ayrshire — run by Finlay and his husband Alan Lambie, taking place today and involving yoga, meditation and some sort of self-administered massage involving tennis balls — sold out almost immediately, despite costing £500 a head.

Or that there is already fevered interest in further sessions at Highgrove and other royal residences, some indoors, some outside.

Or, indeed, that Finlay’s diary is rapidly filling up with private bookings for classes on remote Scottish islands and in castles, often with over-excitable Americans.

Rumour has it the Queen Consort herself is keen to give his sessions a whirl when she and the King have a window. ‘She already does barre and ballet, so I’m hoping,’ Finlay says.

But of course she’s keen. Yoga with a semi-naked kilted hunk? We all are! And it may be just what poor King Charles needs to perk himself up after a challenging year.

‘I get a lot of guys who start at his age. It’s never too late. Almost everyone I work with is over 60 — I like to focus on what people can do, not what they can’t do. And Charles is very forward-thinking, so I know he’d be open to it,’ says Finlay.

The 36-year-old has been creating waves in yoga circles for a while now. As well as being one of the nicest people I’ve met for a long time, he’s a bestselling author, runs a yoga charity with husband Alan called Heart Space, teaches worldwide, has launched an app with free content, sells at least 20,000 copies of his Kilted Yoga calendar a year and campaigns on mental health matters.

But it’s his body that really gets hearts racing — oddly, mostly women’s, even though they know he’s happily married to a man.

‘I think there’s a level of romanticism about a man in a kilt, even if I am taken,’ he says. ‘Perhaps it’s because I’m taken that they feel they can post the comments safely — but they do get quite spicy.

‘I’m very grateful for the “block” feature [online].’

When he appeared by video link on ITV’s This Morning before Christmas for a festive fitness segment — in just a kilt, from the snowy Spittal of Glenshee in temperatures of minus 12C — things really heated up.

‘The producers told me I’d be fine in a coat because it was so cold, then at the last minute they all started shouting “Get your top off”.’

So he did.

In the studio, hosts Alison Hammond and Dermot O’Leary collapsed into giggles as viewers went into a Twitter frenzy, posting lots of ‘Hello there!’ and ‘That’s how I like to see my Scotsman’ comments accompanied by emojis of fires, love hearts and suggestive aubergines. ‘There were some very appreciative comments,’ says Finlay.

‘My mum was scandalised. She’d always wanted me to become a doctor.’

The furore around Finlay really started in February 2017 when, just before teaching a yoga class, he posted a quick video on his social media account of himself and an equally handsome pal called Tristan, both kilted and performing topless yoga poses in the Scottish wilds.

‘I love to practise in forests, up hills, on beaches,’ he says. ‘And I wanted to show that Scotland is breathtaking.’ But it wasn’t just the Caledonian scenery that grabbed the viewers’ attention.

The video was a thing of beauty — strong, graceful bodies moving in tandem, shot by Finlay’s twin brother Alastair and accompanied by simple drums and pipes.

Right at the end, Finlay moves into a headstand and slowly, slowly, with a swish of heavy tartan tweed — ‘it’s supposed to be a bit like the flow of a waterfall’ — the kilt tumbles down to reveal a glimpse of surely the most perfect bottom in the land.

‘It was just a bit of fun — yoga can sometimes feel a bit holier-than-thou,’ he says.

An hour-and-a-half later, when his class was over, Finlay checked his phone and thought the world had gone crazy. ‘I’d had over a million views!’ he says. ‘By the next day it was three million.’ Today, that one post has had more than 80 million views.

Of course, it thrust him firmly into the spotlight. He was on TV, on radio, appeared on the Today Show in America and was interviewed by The New York Times.

Back here, he was popping up everywhere, including on ITV’s Lorraine, where he delivered to his host a ‘happy birthday’ message daubed on his pants — yes, he was wearing some that day — during a final handstand, leaving Lorraine pink-faced and the audience whooping for more.

But while he embraced the moment, he insists he wasn’t in it for the money or fame.

He saw it as a chance to speak about mental health issues in young men, and teach them how to ask for help when they might feel desperate or even suicidal, as both he and his twin brother have at times. And if people liked the look of his bum along the way, then so be it.

Because while today Finlay looks like a Scottish woodland god — chest out, beard trimmed to perfection, skin smooth and silky, muscles bulging as he moves through his yogic salutations — sadly, he knows more than most about pain and suffering. And it was yoga that saved him.

Growing up in Lanark, he was horribly bullied. ‘About being ugly, about being stupid, about everything. It happened all through secondary school,’ he says.

At St Andrews University, where he got an MA in Classics and Geography and was away from his twin for the first time, things spiralled and he started to drink heavily. ‘Every day — vodka, wine, anything I could get my hands on. I’d usually have started by noon.’

He also ate badly and was overweight, deeply unhappy and desperate to come out to his family as gay, but somehow couldn’t. Eventually it got so bad that he tried to take his own life.

And just when things seemingly couldn’t get any worse, a rare medical condition meant he had to have operations on both legs, which left him on crutches for more than a year, caused nerve damage to one leg and damaged his lower back. As the recovery time stretched and stretched, he missed exams and university fun.

It was then that he took up yoga, to help with the pain and recovery. His first yoga teacher sounds awful — telling him to sit out moves because he was ‘too fat’ — but after he found a better one, the weekly sessions became daily.

Which is why he set up Heart Space, where he still teaches at least 16 classes a week — many free — to inspire confidence in children, the elderly, the vulnerable, amputees and disabled people, showing them what they can do. Not what they can’t.

You can see why The Prince’s Foundation wanted him on board. He also does deep-tissue massage and can assess a potential yogi at ten paces.

Including King Charles?

‘Oh yes, his posture is already very good — you can see just from the way he holds his head.’

And while the King may not be quite ready for Wild Thing or Bird of Paradise, he has a lovely selection of kilts to practise in.

‘I’ve got a Dumfries tartan kilt, too!’ says Finlay. ‘So if he comes in his, I’d definitely dress to match.’

However, Charles would ideally wear pants beneath his, as managing not to flash the full Scottish breakfast in a kilted yoga session is a skill few novices possess.

‘It should never, ever be more than the teeniest glimpse,’ says Finlay. And with that, as the watery sun starts to dip and just before his hands and everything else turn blue, he finishes with a final yoga sequence.

Up come the feet, the big calves, the strong thighs, slowly, slowly.

Until the kilt flutters and buckles and then, finally, that promised waterfall of pleats ripples down one by one, to reveal, just for a second, what all the fuss is about.