It's hardly unusual for American teenage stars to be annoying, but Miley Cyrus, the 15-year-old daughter of singer Billy Ray Cyrus, is currently taking the biscuit. Having posed for Vanity Fair wearing nothing but a satin sheet, and having told the magazine at the time that she thought the photo was arty and beautiful, she is now, on publication, backtracking spectacularly.

“I took part in a photo shoot that was supposed to be ‘artistic' and now, seeing the photographs and reading the story, I feel so embarrassed,” she has said in a statement. “I never intended for any of this to happen and I apologise to my fans, who I care so deeply about.”

Disney Channel, whose programme Hannah Montana has made her a star, has also weighed in, accusing Vanity Fair of manipulating her in order to sell magazines. It should at this point be noted that Miley's father was at the shoot, and that, when asked by Vanity Fair's interviewer if she were anxious about the pose, she said: “No, I mean I had a big blanket on. And I thought, this looks pretty and really natural.”

But a lot of money, and Disney merchandise, is resting on Miley's alabaster shoulders. Hannah Montana was an instant hit when first screened in 2006. In it, Miley plays a character called ... Miley, an ostensibly normal schoolgirl who, unbeknown to her classmates, leads a double life travelling the world as Hannah Montana, a singing superstar.

The ratings for Disney's target audience of 6 to 14-year-olds are second only to the scarily successful American Idol. There are Miley Cyrus/Hannah Montana CDs, magazines and sell-out live tours, and a film is due out this year. The show is so big that it has featured on Bart Simpson's blackboard, on which he wrote: “The capital of Montana is not Hannah.” The line where Miley ends and Hannah begins has thus far been blurred, but the Vanity Fair shoot was perhaps a first tentative effort to propel Miley into a more grown-up and endlessly lucrative world (see the Olsen twins).

But what she seems to fear is the outrage of Middle America, which likes its TV stars to be on the goody-goody side of clean-cut. And to make matters worse, the shoot comes hot on the heels of internet photos showing her bare midriff and - gasp - bra, which prompted another apology and an admission that she was not perfect.

Born in Tennessee, Miley has acted since she was 9, when she got a part in her father's TV series, Doc. A committed Christian, she credits her faith with helping to keep her grounded and, like Britney Spears once did, has vowed to remain a virgin until she marries. But with car-crash personalities such as Spears and Lindsay Lohan currently out of action, the pages of America's supermarket tabloids need filling. Miley Cyrus's bare back may be just the thing.

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