Tanya Hennessy on why she can't watch the video that made her famous.

Two years ago, almost to the day, Tanya Hennessy was a radio presenter with 2,000 followers on Facebook.

She was 29, working on a breakfast radio show in Toowoomba and had a degree in theatre and media from Charles Sturt University.

She had wanted to be an actor, but in her own words, “the only job I ever got was like busty prostitute four”. It was because of a showreel, which she sent to TV and radio presenter Jules Lund, that she made her first video and posted it online.

“He called me, which was so crazy,” she tells Mamamia. “[Lund] was like, ‘oh, your presenting showreel’s OK… but I think you need to do really short, funny videos and put them on your page and just see how they go.

“Don’t put them on Youtube. Just put them on your page and just be yourself and be witty and be genuine. And I want to see it. Like, don’t just say OK to me on the phone and walk away from it, I want to make sure you’ve done it.”

So she did it.

Hennessy’s first video, on the differences between being 18 and 30, hit over a million views in a day. In it, she says that while at 18 flirting is all about ‘not needing’ anyone, at 30, (the camera zooms in and music plays that sounds like… doom) you’re thinking: “I need this. I have two eggs left where is this going do you see this ending in marriage I love you.”

The video went viral for the same reason that all her videos - of which there are now more than 100 -  continue to: it tapped into a truth that so often goes unsaid in the highly curated worlds of Facebook, Instagram and Youtube.

Virtually overnight, Hennessy's Facebook page went from having 2,000 followers to 25,000, and when she told Lund he gave her yet another invaluable piece of advice: "keep going mate."

Hennessy's most popular video to date is her 'Everyday make up tutorial', a four-minute parody that acknowledges how a) no one knows what primer is OR what it does, b) foundation you bought at Coles for $10 is... fine, c) sometimes you're just sweaty for absolutely no reason, and d) WHY DOES EVERYONE ON YOUTUBE PULL THESE FACES AFTER A MAKE UP TUTORIAL.

Over 75 million people around the world have watched her anti-tutorial, with countless publications sharing stories about it - from 'Comedian Tanya Hennessy's Spoof Make Up Tutorial Is Hilariously Realistic' on the UK's The Independent, to 'This Realistic Make Up Tutorial Is Going Viral, Because It Sounds Like All Of Us When We Get Ready' on the US's positive women's website Hello Giggles.

I asked the now 31-year-old whether she knew at the time what her make up tutorial video had tapped into.

"I thought it could be great, but I felt like I f*cked it up," she tells me over the phone, after reluctantly having to turn off the soundtrack to Dear Evan Hansen, her latest musical theatre obsession.

"That's why I released it at a random time. I thought the later I put it out, the less views it'll get and I'll have to own it less."

After uploading the video late on a Sunday night, Hennessy woke up the next morning to 400,000 new followers on Facebook. Nevertheless, she says, "I still think that's not my best work".

She laughs as she tries to explain how impossible it is to gauge whether a video will or won't strike a particular chord with her audience.

"It's sometimes frustrating because you go, 'oh I reckon this will go OK,' and it doesn't, and then you release something random and people love it and you're like 'WHY'."

In the last few weeks, it's been what she calls her 'big boob video,' which has attracted interviews from a number of US publications. "It went crazy," she says. "And I was like, 'really? I don't even know about that video?'"

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Hennessy's unmistakable imposter syndrome rears its head more and more as she's speaking to me, which she's doing while on her way to Sydney for a work commitment with Channel 10.

"I don't really like any of my videos," she says casually. "I find it really tough. I never watch them back. It's weird... people quote my videos back to me and I'm like, 'I don't know what you're quoting'."

"I don't know if it's a girl thing or a creative thing, you just never rate your own stuff," she says. "Even when I'll be told amazing stuff from like Comedy Central or the ABC, and I'm like, 'umm, they're lying'. I believe that. I believe people lie to me."

"I just don't believe that I'm very good. I wonder when that will change. I have such an inferiority complex... I don't think it's good, I don't think I'm funny, I think I'm fooling people."

What's fascinating, however, is that her lack of faith in her own abilities doesn't get in the way of her ambition. When it comes to her career aspirations, she's clear and honest.

"My goal is to make really, really great comedy," she says. "I want to collaborate with some more people, I'd like to write a TV show. My goal is to do a TV show, but I want to write it."

She references Ricky Gervais and Chris Lilley as people who have done what she's desperate to.

But for the moment, she insists that despite having almost one million followers on Facebook, and being recognised everywhere from Canberra to Sydney to New York to LA, she's not a celebrity.

"I wear the same pair of jeans every day, my undies don't fit, I'm barely wearing socks and when I do, they don't match. I've got a double chin, I've got a thyroid issue, I live off Cheezels. So when people are like 'you're a celebrity,' I'm like f*ck no I'm not, I shop at f*cking Cotton On because I can't afford Witchery."

And that, in a nutshell, is the secret to her success.