Grown-up Miley puts Montana behind her

It is the hardest transformation in Hollywood: the change from beloved child star to successful adult celebrity.

Now Miley Cyrus, who as her alter ego Hannah Montana has been perhaps America's biggest child phenomenon, is attempting to walk that road. At stake is not only Cyrus' career, but an industry built around her that has been estimated to be worth a billion dollars.

Last week showed just how difficult Cyrus might find it. Celebrity blogger Perez Hilton tweeted a paparazzi photo of Cyrus that allegedly showed her without underwear, creating a storm of controversy, not least because, with Cyrus being just 17, such a photo could legally be seen as child pornography.

The row was embarrassing for Cyrus and her management but it showed how delicate the transformation is between child and adult fame.

Cyrus has already outgrown the Hannah Montana role that made her globally famous and the star of her own TV show when she was just 12.

She has cast off the image of a hapless innocent "tween" that won over a generation of young Americans and started to pursue a more adult singing and acting career, taking on controversial film roles and sexualising her pop music.

Her once wholesome girl-next-door image has been shed for increasingly revealing risque outfits. She has started dating an actor, Liam Hemsworth, who is three years older than her. She starred opposite him in a recent film, The Last Song, which included long kissing scenes.

Her stage show performances have started to look more like a Madonna concert than that of a tween star and one-time country music favourite. Her act has included a brief pole dance and a suggestion of a lesbian kiss. She has even got several tattoos.

Some experts think that she is going too far. "We are seeing stars like Cyrus take the risque approach to transforming their identity by letting her sexuality lead the way," said Ashley Dos Santos, a celebrity expert at communications firm Crosby-Volmer.

"Cyrus is equating growing up with hyper-sexuality - dressing provocatively and promoting the idea that she can't be tamed."

Britney Spears also cultivated a homely image when she was a child star. She was a former member of Disney's Mickey Mouse club who, when she emerged as a pop star, put great public emphasis on her virginity and wholesome relationship with fellow teenage star Justin Timberlake.

When Spears tried to transform into a more adult star, she employed the same tactics of ever more overt sexual antics in her stage act while her private life grew more chaotic.

For those growing up in the glare of modern publicity, a single mistake can create global headlines and destroy a career. Cyrus herself has rarely been out of the public eye since she was very young. She was born into a showbusiness family led by her father, the country singer Billy Ray Cyrus.

Her every move has been documented and followed by paparazzi. A picture of her first kiss was once estimated to be worth up to US$150,000. Almost anything she does - from an update on Twitter to a scantily-clad photo shoot with Annie Leibowitz - causes headlines.

"The public is watching her every move. The normal mistakes she will make as a teenager will be 100 times bigger for her," said Dr Leslie Seppinni, a Hollywood-based psychologist.

But not every child star crashes and burns. Britney's former boyfriend, Justin Timberlake, has consciously used overt sexuality as one of his selling points, and has sold nearly 20 million albums.

"There are absolutely ways to make the transition," said Dos Santos.

But, for now, it remains to be seen whether or not Cyrus will be able to do it.

A Difficult Age

* Justin Timberlake: Achieved worldwide fame in boy band 'N Sync. But he has now shed his tween heartthrob image for that of a highly successful adult solo pop singer. His acting career is also prolific.

* Judy Garland: Hit global fame in The Wizard of Oz as Dorothy. She made the successful transition to celebrity as an adult in both music and acting, although she battled personal problems including an addiction to prescription drugs.

* Drew Barrymore: Her path from child star to adult celebrity was a notoriously difficult one. The star of ET suffered burnout at a young age but emerged as a successful Hollywood actress who is now moving into directing.

* Jodie Foster: Shot to stardom as the child star of Bugsy Malone and Taxi Driver. She became one of the most successful and talented actresses of modern times with acclaimed roles in Silence of the Lambs and The Accused.

- OBSERVER