Miley Cyrus' audition tape for the Disney Channel's "Hannah Montana" can be found on YouTube. In it, the 12-year-old Cyrus is sporting frizzy hair, a big smile- and, amazingly, even then her trademark whiskey drawl when she talks. She displays the practiced poise of all child actors - a fearlessness when it comes to staring straight into the camera and reciting her lines - and her posture and mannerisms  reveal that she knows this is a business  opportunity and not a social call.

Flash forward five years, and Cyrus' latest YouTube offering, her video for the title track off her album "Can't Be Tamed," involves a birdcage set that doubles as a pole-dancing playground, writhing background dancers and an outfit notable for its feathers and decolletage. Like Disney teen idols Britney Spears, Christina Aguilera and Justin Timberlake before her, Cyrus is now making the often-murky transition into adult artist. The June 22 release of "Can't Be Tamed" is the boldest statement in a years-long process of transitioning Cyrus away from the scrubbed cheeks and all-American girl charm of "Hannah Montana" to a modern pop diva.

"I'm just at a certain place where I've changed a lot as a person," she says. "I've grown up a lot, which everyone does."

Photos: Miley Cyrus & Her Famous Friends

Everyone does-but very few have to do it in the public spotlight with all the divisions of Miley Inc.-from film to TV shows to voice-over work to apparel - riding on the success of the transition. It's no secret that Cyrus has been publicly testing the waters of adulthood for the last few years-making dramatic displays like the bed-head Vanity Fair photos or the vaguely stripperish dance moves at Nickelodeon's Teen Choice Awards-followed by an equally dramatic retreat.

Her music has followed a similar act of toeing the line between tween and adult, with singles "The Climb" and "Party in the U.S.A." offering a far different message from earlier teenybopper tracks like "See You Again" and "7 Things."

On the eve of the video debut of "Tamed" on May 4, Cyrus knows that it's going to ruffle some feathers. "You're going to, like, die when you see the birdcage in the video because it's so crazy," she says. Despite Cyrus' march into adulthood, she still talks like a teenager-all rapid-fire patter that, by my transcribing tally, comes in at around 200 words per minute. "I've got, like, 30 dancers in there and a tree and a nest. Literally, it's out of control. I'm definitely going to be doing a lot more stuff like that."

The immediate sales response to Cyrus' new image seems to be positive. For the week ending May 23, the single's first week of digital sales resulted in 191,000 downloads, according to Nielsen SoundScan, placing "Tamed" at No. 4 on Billboard's Hot Digital Songs chart and No. 8 on the Billboard Hot 100. The song also rose 35-28 with a bullet on Mainstream Top 40.

"Miley's transformation was inevitable-she's been clawing herself out of that cage for a while," says Suzanne Ross, executive producer of E!'s "True Hollywood Story" and "E! Investigates." "I'm surprised it shocks people anymore. It's an inevitable part of growing up Disney. It's a formula, from what I've seen from past stars: Disney makes you a star, you make them an enormous amount of money, and then you either crash and burn or you go out and stake your claim in the real world."

NEXT: The Making of 'Can't Be Tamed'