These are some of the things I learnt during four leisurely phone chats last month, and even before that, I felt I knew them already. Do I even need to use their surnames? The first names of the four newest Wiggles are surely, by now, well on their way to entering the lexicon of the Australian childhood.

Clearly, it’s finally happened to me. I don’t exactly regret the moment when I pressed “order” in the app store, but I have to admit that I didn’t expect to have songs by The Wiggles on an endless loop in my living room – and, by extension, in my head all day long – quite this early. I thought I had at least another year before the advent of coloured skivvies and repetitive songs. But the voraciousness with which my toddler has taken to The Wiggles has taken me aback.

In retrospect, though, I shouldn’t be surprised. I first came into contact with the Wiggly juggernaut three years ago, when I was only just pregnant, and was called to cover a show for work. It was during the group’s 20th

But what really shocked me was how much the four actual Wiggles seemed to be enjoying themselves. They seemed … blissed out. And as they descended the stage to collect roses for Dorothy the Dinosaur from eager kids – a time-honoured tradition, I later learned – faces everywhere spelled pure gratitude and joy. It was, for an as-yet non-parent, truly surreal. What was this strange witchcraft?

And now, in the brave new era of Wiggles 2.0, I’m starting to realise. Watching one of the group’s latest singles, Do the Propeller, which, at the time of writing, has had more than 1.8 million hits, I am strangely compelled. It’s an oddly joyful, nutty song, with hardly any words but some highly energetic dancing. Wiggles 2.0 are clearly enjoying themselves, and my two-year-old can’t get enough of it.

It’s time to get to the bottom of this.

By now, the stratospheric success of the original wholesome foursome is well-known. At one stage, not that long ago, they were Australia’s richest entertainers. Concerts routinely sold out all over the world. Celebrities and their celebrity children visited them backstage. Merchandise was through the roof, and parents, stuck in the middle of it, sang the songs like automatons, while their gratitude morphed into the contempt of the over-familiar once the kids were, finally, past the Wiggly age.

The Wiggles were, I was reliably informed, a rite-of-passage for all modern parents. But, in the gap between the 20th anniversary tour in 2011 and my daughter’s first hit of the thoroughly nutritious Wiggles drug, something changed. The Wiggles retired, and then were regenerated, with the yellow skivvy accompanied by a skirt. Parents grumbled. Nostalgic teenagers waxed lyrical about Murray, Jeff and Greg, their lost heroes. Twitter was filled with snarky comments about the new line-up. Kids now are just as likely to be getting their first taste of their music via an app or a Youtube clip than a DVD or on the television. And, more interestingly on a practical level is the fact that, after a year of endless regional touring and plenty of empty seats, the next Australian tour, happening in December, sold out in record time, with new shows being added every day.

I had vaguely assumed that getting onto The Wiggles would be a drawn-out process. I thought perhaps the four members would be cagey, stage-managed, distant and polite at best. I had a notion that the new members had been carefully selected from thousands of candidates and would talk at length about what a thrill it was to be in “the team”. I certainly didn’t expect Emma Watkins, Lachy Gillespie, Simon Pryce and Anthony Field to each call me separately from their own mobiles, and chat at length about their gruelling year of trying to win back the legions of three-year-olds that once adored the brand.

Over four long – and very relaxed – conversations, here are some of the things I learned:

Founding member Anthony began looking around the Wiggles company as soon as the group decided to retire, searching out potential new members.

One of them, Lachy, was completely unfamiliar, as he’d been cast for the Dorothy the Dinosaur show, which has a separate director. But once Anthony began to take notice, he knew he’d found someone to wear purple.

“Apart from being a WAPA graduate with the sweetest voice, he’s just the nicest man,” he says.

“And if you’ve done the Dorothy show and you’ve survived and you’re happy, you’ll be a good guy on the road, you’re not going to be complaining about anything. Nothing’s going to throw you.”

Twenty-eight-year-old Lachy was star-struck the first time he met the Wiggles in person, despite having been dancing in the Dinosaur show for a year. And when he was eventually asked to dance in one of the main shows – a career goal in itself – he had no idea that he was being surreptitiously auditioned to eventually don the purple skivvy.

He found the first shows difficult, and made the mistake early on of reading comments on Twitter.

“It was horrible. It’s not a nice feeling at all to read, ‘That’s not the Wiggles, who they heck are they, what are they doing, get off’, and all that stuff, and I think the best thing was to just get out there and do the shows and realise what impact we still had,” he says.

“It didn’t really matter who was in the skivvies as long as the music was good and the characters were there and the colours were there … To see a live show now would be a completely different thing to seeing our first live shows.”

Simon had been working with the Wiggles for around 15 years before he finally became the red skivvy. With his deep baritone – he played the Phantom of the Opera twice a week as understudy to Anthony Warlow back in the '90s, racking up some 140 performances – he had been contributing to the group’s recordings to add vocal depth. He was also a wit onstage, and Anthony picked him as a potential father figure to the younger recruits.

He has learned that, as kids grow up, it becomes daggy to enjoy The Wiggles. But then, it becomes cool again.

“A friend of mine has a 12-year-old, and when he told her that I was going to be a Wiggle, she said, 'that is SO embarrassing'. But then when they get a bit older, it becomes really cool again to have fond memories.”

And 24-year-old Emma, the flame-haired, multi-talented "young Wiggle", was a no-brainer. A dancer, a singer, a filmmaker, trained in sign language – the fact that she was female never came into it.

“When Emma joined and she was wearing a dress – it’s such a funny old world – there were complaints that we’d put her in a dress,” Anthony says.

“Emma’s one of those young women who loved to wear bows, and that was her whole thing, and so the Emma character in the Wiggles is a whole extension, and she’s never in pants.”

But, two years down the track, and Emma has amassed a huge collection of bows given to her as gifts at shows – and sees them on the heads of kids throughout the audience, even the boys. And some of these boys even put on skirts for the shows. Go figure.

But 2013 was a hard year. Bright-eyed and setting out on a new adventure, the four travelled the country, end-to-end, playing countless regional shows. It wasn’t easy. Sometimes they drove for six hours, to play to an audience of 60. Even the big city shows didn’t sell out.

But they knew they had to work hard to create a new generation of audiences, a task made even harder by the fact that parents have longer memories.

“Even though we gain an audience every year with babies being born, we lose them every year as well,” says Emma.

“I think that’s what happened last year, we had such a big job trying to gain the audience back over a period of three years in the space of one, so it was really difficult, but it has turned around. We worked really hard.”

And, says Simon, when it comes down it, it’s parents who have trouble with change, not children.

Do the Propeller was shot in a London laneway, with the group dancing to a recording of the song on an iphone. They were still just Wiggles-in-training, donning the skivvies for the first time. At one stage, a resident came out to tell them to pipe down. He had no idea who they were.

“I was filming it, so I had to set up the tripod and everything, and then when I was in the shot I had to get Jeff to press record, so that’s why Jeff makes a cameo,” says Emma.

Part of it is also shot on the top of a London bus.

“My favourite bit is where the flag falls off when Lachy’s just waving it around,” says Simon.

“We were just on the top of the bus, we just bought tickets on the normal bus and just started singing in the back. It was hysterical.”

Social media and new technology have helped the Wiggles with their renewal, but in the end, the group's long-term method hasn't changed, and it’s still all about entertaining kids. At the time of our interview, a new Wiggles video is in the process of going viral, but it's one more aimed at adults, a parody of the Suarez shoulder-biting scandal during the soccer World Cup.

It’s something the old Wiggles probably wouldn’t have attempted, but Anthony says he was worried that children were seeing a controversy around bad sportsmanship, and the video aimed to make light of the incident. Kids, in other words, are always at the centre of what they do.

“People say to me all the time, you’re lucky you get a new audience every three years, but you lose your audience every three years so you have to have something that connects,” he says.

“You can’t take for granted that children are going to like the Wiggles, you have to have good product.”

Ultimately, redefining The Wiggles for a new era was a gamble that paid off, Twitterati be damned. And never mind the parents; Anthony says he no longer worries about what his old comrades, Jeff, Murray and Greg, would think. This is the brave new era of Emma, Lachy and Simon.

The Wiggles are performing at the Canberra Theatre on December 9.