1. Kayla is a #totes #fitspo #phenom at just 23

So how did the Aussie personal trainer manage to become the most buzzed-over figure in the fitness game – and the subject of breathless features in Cosmopolitan, Elle, Marie Claire, the Daily Mail and so on – at such a young age?

Well, it helps that she’s been in the business pretty much from the moment she left high school. “Once I graduated school, I actually started studying beauty therapy,” Kayla recalls, “but my love of sport led to me to personal training, and I quickly discovered how much I loved helping people become healthier and happier.”

Awww, so that’s nice, isn’t it. She seems nice, no? And that inherent niceness is a big, big part of her appeal…

2. She has more Instagram followers than you

A whopping 3.1 million Instragram followers, to be precise. If you’ve got more than that, we stand corrected. But you haven’t, have you. Naaah, you ain’t.

Plus! Kayla’s Facebook page has 1.8 million likes. Also! She has 205,000 Twitter followers.

And her fans are fanatical – she basically has her own army. If she told all her social-media followers to invade, say, Puerto Rico, they probably would.

She recently hosted a huge free workout class in London – places for which vanished in seconds – that had the kind of fevered, ecstatic atmosphere you’d normally associate with cult rallies.

3. Her books ain’t cheap, but people swear by ’em

Kayla has released two ebooks, Bikini Body Workouts and H.E.L.P. Nutrition Guide – the latter of which comes in two flavours, Regular and Vegetarian. Both books go for a whopping $69.97 a pop – pretty hefty. Or you can get both for the low, low price of $119.97 – still pretty hefty.

Her books go for a whopping $69.97 a pop

But! Kayla’s site is nevertheless filled with ringing endorsements from satisfied customers. “I’ve never felt as comfortable in my own skin or as proud of myself as I do now,”says Lani Belle; “I look in the mirror and like what I see. These guides are truly the BEST!” says Hannah Udina.

She used all-caps on “best” so she must really like them.

4. Oops, Kayla got famous by mistake

She may have more Instagram followers than she knows what to do with, but Kayla claims there was no grand plan to make that happen. In fact, when she first started posting her clients’ before-and-after pics to Instagram, she mistakenly thought it was a private photo-storage service.

I know this sounds stupid, but I didn’t know people could see what I was uploading

“I know this sounds stupid, but I didn’t know people could see what I was uploading,” she says. Honestly? That does sound a bit stupid, but carry on.

“I didn’t know what was happening: people were following me on Instagram and asking me about what I was doing, and I realised they were ‘commenting’. I know it seems silly now!”

It’s okay Kayla, we all do daft shit sometimes. Anyway, things quickly snowballed for her. “I didn’t want to make a name for myself,” she shrugs, “but it just… blew up. I can’t explain it. It’s crazy!”

5. She’s the queen of the before-and-after pic

Kayla’s website and social-media channels are filled with before-and-after pics from women who’ve followed her programmes – and some of them really are pretty amazing. (Some of them really aren’t, but you can’t win ’em all.)

However, Kayla’s started to distance herself a little from jaw-dropping transformation pics, which can be fairly easily faked, if you’re particularly desperate for validation from strangers on the internet.

Anyone can sit there, push their stomach out and make their legs bigger

“Anyone can sit there, push their stomach out and make their legs bigger [for a ‘before’ photo],” says Kayla. “And if you want to do that, that’s fine. But what I do is I tag the girl whose photo it is in the caption, so that you can click into her account and see her step-by-step transformation

“We’re very picky with who we upload. We don’t want to upload an account that just has one transformation. We want to watch their body change, and I think that’s the difference.”

6. She’s introduced millions to gettin’ sweaty

Kayla reckons her success is down to the simplicity and intensity of her 28-minute workouts. 

“I think that’s what people love about my program: I’ve taught them you don’t need to kill yourself at the gym. It’s 28 minutes, it’s high intensity, and then you’re done.”

I’ve taught people they don’t need to kill themselves at the gym

Given our hectic 21st-century lifestyles – filled to the brim with meetings, Pret sarnies and Orange Is The New Black binges – 28 minutes is all many of us can spare.

“I understand that people don’t have time to drive to the gym,” says Kayla. “The gym might be 20 minutes away, so that’s 40 minutes of your day wasted, plus the time it takes to do your workout.”

But if you claim to have no time to exercise, Kayla is not interested in hearing your crap. “Yeah, you do! You have time. Everyone has time!”

You heard the lady.