Meet the mini-mice: What does it take to make a Miley Cyrus?

Once upon a time, there was a little girl. She had a dream... to be a princess. But not just any princess – she wanted to be a Disney princess.

And, once upon a time, a Disney princess was a cartoon – complete with a pink frothy gown, a Prince Charming-in-waiting, and possibly some forest animals gambolling round her skirts and glass slippers. Today, a Disney princess is quite a different construct.

For starters, she's a teenager. She's a kind of hyper-real take of the girl next door: perky, poppy, super-fun, but squeaky clean. She's made her name by starring in a Disney Channel sitcom, but she's become a crucial cog in the Brand Disney wheel – her mere presence can flog a film franchise, shift millions of records, and launch a thousand products, from pencil cases to fashion lines.

Tweenage girls – let's define them as being between the ages of nine and 14 – will be well versed in who these show-anchoring, precocious talents are, in the UK too: the Disney Channel is the top pay-TV channel for that demographic. But even if you've never watched it in your life, you're probably aware of the stratospheric stars it has spawned.

Back in the Nineties, The All-New Mickey Mouse Club – an updated version of a Fifties variety show programme on the channel – launched the careers of its little 'Mousketeer' presenters, a roll-call which included Justin Timberlake, Britney Spears, Christina Aguilera and even Oscar nominee Ryan Gosling. Then there were Disney Channel Concerts, which gave a stage for the Mousketeers, as well as other mini-popstrels like LeAnn Rimes and the Backstreet Boys, to launch singing careers.

Could these two entertainment streams be mixed? Yes, and when they were, the resulting shows-with-music would prove to be catnip for pre-pubescent girls, allowing Disney to colonise not only the tweenage TV and film market but also the music industry. Many of the next generation of big names from the mid-Noughties started in this way: Miley Cyrus in the hugely successful Hannah Montana; Zac Efron in the High School Musical movies; the Jonas brothers and Demi Lovato in the Camp Rock movies. They act, they sing, they dance. And they certainly sell.

In the last quarter of 2011, Disney's cable network profits grew to a whopping $1.3bn, thanks to the worldwide expansion of the Disney Channel. Across Europe, the Middle East and Africa, figures have trebled in the last three years: 100 million homes now have the Disney Channel.

But if you pin your success on a five-year age range of audience, you're also restricting yourself. Its young stars go from dreaming of being princesses to becoming fully-fledged Tween Queens, with international reign – but eventually, little girls grow up, and so do their viewers.

For the powers that be in the House of Mouse, all this creates a constant pressure to find the next Miley, the next Selena. Every show needs an anchor, a girl who viewers will fall in love with. And whatever one thinks of the shows (and if you're not underage, you'll almost certainly think them maddening and unfunny), you'd also have to admit most of tween queens have got a certain something, that indefinable star quality.

Keeping the empire peopled with charismatic pre-teens is Disney's vast behind-the-scenes talent-scouting machine. I speak to Judy Taylor, who's been in the casting game for 38 years; she was responsible for Hannah Montana, The Cheetah Girls, High School Musical and The Suite Life of Zack & Cody. In Disney Channel terms, she's a Cassandra on uppers, forever prophesising the Next Big Thing.

"There is the need to have someone who can actually anchor a show," she explains. "We're looking for that 'relateability' – and that charisma, x factor, whatever you want to call it – and that's the most challenging."

How does she know when she's found it? "For me, it's that feeling of not wanting to stop watching them. There's just something that... pops." She runs through a few of her lightning-bolt finds: Miley was "unforgettable"; with Selena she "knew instantly"; Debby Ryan was "immediately set apart". You've either got it, or you don't, kid.

And when they've got it, Disney gets in there quick. Many of their young stars will do several pilot episodes, or be kept on the books till the right vehicle comes along – or even gets created specially for them. These child stars really are one in a million. And to find them, Disney has to cast the net wide.

"We do travel round the country quite a bit," says Taylor, who organises annual talent searches. Being based in LA, they also see auditions every day. "We have the kids come in, get a good idea of what they're like as people, and have them read material for us. But going round the country has also made for some wonderful discoveries in f the past." Disney's scouts look across the US and beyond. Gregg Sulkin was a "great discovery" from Britain, who starred in As the Bell Rings; London girl Naomi Scott was in last year's Disney Channel movie Lemonade Mouth and this year graduated to Steven Spielberg's sci-fi series Terra Nova. "You just never know where they're going to pop up!" enthuses Taylor.

Disney's next hot tip is China Anne McClain. China is the 13-year-old star of A.N.T. Farm, a sitcom about unusually gifted kids; China's talent, of course, is singing. In real life too, she has a record deal; she released her first A.N.T. Farm album in October.

"We met her initially back in 2006 – China was only eight and she blew us away," raves Taylor. But she got offered another part, in comedy-drama Tyler Perry's House of Payne, filming near her home in Atlanta, Georgia, and opted for that instead. "We never forgot China. So in 2009, she found her way back to us, and it was that commitment: we want China on Disney Channel. She was incredibly versatile – she was already such a sitcom dynamo."

You could be forgiven for having never heard of China, but you will – and your average British tween probably already has. A.N.T. Farm launched in the UK in October; within a month, it had been seen by 2.9 million people here. (That breaks down to 600,000 eight- to 12-year-old females, meaning more than a third of all tweenage girls in this country have tuned in.)

Speaking to China, she sounds – as you might expect a 13-year-old on the verge of world domination to sound – pretty excited. She was discovered when a friend of her dad's saw her prancing around at home and introduced her to a filmmaker. "It was actually a coincidence – I did not know that I loved acting or even that I could act till that day," she says. "I was five or six, I had to learn a lot about how to take directions, but it came pretty natural, and I loved doing it."

She's chirpy and full of laughter. But child stardom is a perilous path; the eventual fates of some of the Mousketeers taught us that. Think of Britney's meltdowns, Lindsay Lohan (star of Disney family films The Parent Trap and Freaky Friday) and her pressure-cooker combustion, even Christina Aguilera's almost violent self re-invention as raunchy, x-rated Xtina.

The next generation of Disney stars haven't been immune either: Demi Lovato checked into rehab after suffering from eating disorders, self-harming – and attacking a backing dancer. Miley Cyrus deliberately

shirked her clean'n'cute image with provocative photoshoots and, presumably less deliberately, in a video of her taking bong hits.

I put it to China that there's a lot of pressure in becoming so famous at such a young age. "Well, to me it's kind of surreal," she begins. "I don't think it's a lot of pressure. But it's definitely something I'm careful of – it's not that hard now, because I'm so young, but I am aware of it."

You can be damn sure Disney are careful too. They've been burned before by protégées going rogue. Part of the brand's success is that parents know it's safe and wholesome. Not that you get a peep out of anyone at Disney about how they rein in their young stars. It's been reported that casting execs vet parents as thoroughly as the kids these days, but this is merely presented as normal life within being one big, nurturing, happy family.

"Growing up and being a teenager is a difficult journey no matter what you're doing," starts Taylor. "Often [they] are growing up in front of everybody, I think they handle it amazingly well... people are used to hearing about [pushy parents and rebellious children] because whenever there's a difficult situation that's what tends to be in the forefront, but these families make a lot of sacrifices. I give them a lot of kudos for upsetting what was probably a normal life."

China, unprompted, echoes: "it's like a great big family." She is bouncily positive about how they are "always so open with whatever I want to do", and when I suggest that this is to help her develop the China brand, she says, "Exactly."

This awareness of personal branding, from a 13-year-old, is a little queasy-making. The shows may portray happy, tweenage lives – but their stars are mini-businesswomen. Disney gives new recruits their 'Talent 101' training: from prepping them for lifestyle changes to telling them how to deal with the media. They need these skills; several million dollars is resting on their narrow shoulders.

It's something I'm acutely aware of when I meet Debby Ryan. Star of Disney sitcom The Suite Life on Deck, and now record-breaking hit Jessie (4.6 million viewers saw its US premiere), she is a Disney girl done good: she joined the channel at 14, and is still with them at 18. But this driven young woman wasn't shy about creating her own opportunities: she helped come up with the concept Jessie, in which she plays a nanny to younger kids.

"I don't think I have outgrown Disney, so I took a few ideas into a pitch meeting," she tells me. Bright, eloquent and ferociously focussed, she's clearly learnt how the industry works. For Debby, the 'Disney family' has meant she's managed to step up from starlet to having some level of creative control – or at least, not being afraid to knock on doors. She sits in with writers; started her own record company; hired her own stylist; helped cast Jessie. All before she could legally order a beer.

She plays the big sister role off screen as well as on, offering advice to younger stars like China. But Debby is also candid about what fame can do to the underage ego. "China has been incredibly gracious, and nothing is going to stop her. But there were other stars I did the same thing for, and they now – 13-year-old girls! – walk up to me and say "sweetie"... Absolutely, I have seen [big egos] first hand."

Surely Disney must try to control her, and her image, as she approaches the dangerous transition age? "I feel like there is a bit of packaging, but not in an artificial way. I can't think of a Disney representative that tells me what to like or what to mention," she insists.

Although Debby is all made up with pouty lips and high heels, something tells me she's too steely to go off the rails. "Disney are allowing me to grow. They take me seriously, creatively, professionally, as an actor but also as a teenager. Because of that, I haven't felt the need to prove anything."

Perhaps the new generation of Disney princesses won't be pole dancing in suspenders to prove they're all grown up; it'll be taking over the world by – literally – running their own show.