If you’ve spent any time online over the past week or so, there is a good chance you will have come across a certain video. The clip, which is about 45 seconds long, shows two Scottish men performing yoga in a tranquil woodland setting. You know they are Scottish because they are wearing kilts. And — crucially — very little else.

They are ripped, shirtless and beardy, and even though they look like an act you would book for a Braveheart-themed hen night, there’s something mesmeric, calming and, well, just very funny about the whole thing. They conclude their exercises by performing headstands, their kilts falling away to reveal a pair of pert, pale, Celtic backsides. The video has been watched 50 million times and counting.

But who are they? And what are they playing at? Well, the one with tattoos is Tristan Cameron-Harper, a model and former professional ice-hockey player. The one with the ginger beard is Finlay Wilson, a yoga instructor. They’re from Dundee and want to show people — particularly men — that it’s possible to do yoga without being po-faced.

“We wanted it to be light-hearted without disrespecting the practice,” Wilson says. “Some people take it so seriously they actually lose their way with it. And it puts people off. But I’m all about getting more people into yoga, and making sure it’s fun and engaging.”

Back to nature: the Warrior I pose

Wilson says that in spring and summer he’ll do lots of (fully clothed) yoga in the countryside outside Dundee. “It’s the perfect environment,” he says. Does he ever startle groups of ramblers? Children doing their Duke of Edinburgh’s award? “You make it sound like it’s dogging,” he says with a giggle. “Fair enough, if I was butt naked I might upset a few people. But when I practise yoga outside, I find that people engage with me more, come up and ask me questions.”

Wilson roped in Cameron-Harper, who is a regular at his classes, to take part in the video. He didn’t need much persuading. “I love the outdoors, so it all felt very organic,” he says enthusiastically. Still, it got pretty chilly. “You can see we’ve got lots of goose bumps and hard nipples.”

And, funnily enough, the video has resulted in a deluge of smutty fan mail. “Some pretty explicit stuff,” says Cameron-Harper. “People saying we should make a sex video and put it online.” He laughs at the thought. Honestly! He just likes doing yoga. Sometimes outside. With his mate. Nothing wrong with that. In fact, more men should do it. “It’s been great for my body and it’s really helped me to feel more relaxed.”

Wilson says the joint bum-reveal at the end of the video was his idea. “When people see a kilt, the first thing they think is, ‘What’s underneath? Is he a true Scotsman?’ But it took about 40 takes to get Tristan upside down, because he’s not been doing yoga as long as I have.” Plus, once he managed to do a headstand, Cameron-Harper says his kilt wouldn’t fall away properly. “Which is why you see me shaking my arse around, trying to get it to move.”

The whole thing, they emphasise again, is just a giggle, but hopefully one that serves a purpose. “It’s showing a beautiful Scottish environment. It’s showing guys doing yoga, which is rare enough. And it’s showing Scottish guys who aren’t overweight or obese,” says Wilson. “And then there’s the little surprise at the end. A lot of people have said they didn’t expect it to make them smile as much as it did. That’s been the main message. ‘This made my day. This really cheered me up.’ ”