Even in a concert film, Montana/Cyrus is a hot ticket

Now, and quickly, comes a 3-D movie version of the stage show. Playing in theaters for one week only (and not previewed for film critics), it opened nationwide yesterday. One's opinion of it may depend more on age and parental status than exposure to other rock-concert films. But there's no denying the film delivers on its promise: 74 minutes of Hannah/Miley doing her/their full-throated, pop-superstar thing.

"Best of Both Worlds" is not just the title to one of Cyrus's biggest hits, of course, but the conceit underlying the Disney show, in which Cyrus plays a Southern California teen living a secret double life as a pop star. Beyond that, "both worlds" neatly sums up the duality of the lives Cyrus and her audience are leading, or at least wish to: straddling the fence between girlhood and young adulthood, innocence and budding maturity, girl-next-door life and fantasy-star existence.

Both worlds are served in the movie, the first half of which features Montana - she's the one with the long blond tresses and NutraSweet persona - and the second half given over to Cyrus, whose hair and music are both a couple of shades darker than Montana's (but barely). Each is allotted 10 songs or so, with another two handled by the Jonas Brothers, a tween-sensation band that toured with Cyrus.

The stage setting is tricked-out arena rock at its gaudiest: multilevel platforms, multiple video screens, pyrotechnics, enough dancers and backup singers to float a Broadway musical, and a walkway that projects performers right off the screen and into moviegoers' laps. The camera also ducks backstage and behind the scenes to capture Cyrus as she rehearses for the tour or prepares for her next stage number. Her mother and father (country star Billy Ray Cyrus), make brief appearances, too, as do many young fans serving to put a face, and a really cute one at that, on the Hannah/Miley phenomenon.

To point out Cyrus's vocal limitations seems, well, pointless. She sings and dances ably enough, and her tunes (she writes, too, including one song poignantly dedicated to her late grandfather) surpass much of what's heard on Radio Disney. She has boundless energy, a wardrobe that won't quit, and enough real teenager in her to come across as more than a mere Disney creation. Where she'll be in five years is anyone's guess, but one hopes it's not in rehab. That would be the worst of both worlds, and a depressing movie to watch.

Joseph P. Kahn can be reached at jkahn@globe.com.