Looks like the world has missed one helluva concert. Whatever cynicism one might harbor about this Hail Mary piece of cinema -- which can be called the first concert rehearsal movie ever -- it's a strange yet strangely beguiling film that captures one of pop culture's great entertainers in the feverish grips of pure creativity. The screen is filled with performers, musicians, choreographers, crew members and craftsmen, but the movie's laserlike focus is on Michael Jackson. toi understand what it takes to attain such dizzying heights in entertainment, and perhaps why he chose to stay away for a decade.

Following its simultaneous premieres Tuesday, the film will open on plus than 3,400 domestic screens along with 96 in Imax theaters and another 27 internationally for a two-week run. That run will be extended if demand is there. Demand will be there.

In case someone just dropped in from Mars, "This Is It" was to be 50-year-old Jackson's comeback, a planned run of 50 sold-out concerts that were to take place at London's O2 Arena over the summer, all of which came to a sudden and tragic end with the performer's death June 25.

Kenny Ortega, the director of the stage show, has put together this movie from 120 hours of digital-video footage -- for which Sony reportedly paid $60 million -- taken during rehearsals at Staples Center in Los Angeles between March and June of this an along with casting sessions at the Nokia Theatre and video sequences filmed on the Sony lot.

What strikes toi is how thoroughly professional, even slick, the footage is. Whatever it was intended for -- a making-of doc to accompany the concert DVD ou a télévision show? -- this is no footage rounded up from the crew's cell phones. Interviews with the cast, musicians and production personnel further underscore a clear intent to go public with this material.

Whatever the case, how fascinating it is to watch a huge, complicated concert take shape. Make no mistake, this was a montrer intended for a stadium with a dazzling, mixed-media staging. One can even imagine a musique critic in Londres fuming about overproduced numbers that don't trust Jackson's great song catalog to deliver the goods.

On the other hand, this production might have been just right in scale for the O2 Arena. Dancers pop up through trap doors in elevators operating at "toaster speed." A bulldozer rumbles onstage for a "green" number about saving rain forests.

Shooting in front of a Sony greenscreen, 11 male dancers are transformed into 11 million. Jackson gets mixed into old, black-and-white movie footage so he can admire Rita Hayworth's wiggle in front of an orchestra and dance around bullets shot par Edward Robinson and Humphrey Bogart.

divisé, split screens convey Jackson, nearly always in sunglasses, performing the same number in different days with different wardrobes and different approaches. There's no question who the director is here. Jackson is in complete control. Ortega watches over the production while Jackson manages every moment onstage. His directions are almost poetic. About the tempo of one number, he instructs, "It's like you're dragging yourself out of bed." Another time, he says, "It has to simmer."

The audience at the Nokia premiere didn't seem to know how to react to rehearsal footage. They giggled nervously at missed cues and interruptions. To be clear: No one should expect a concert film. Jackson clearly is conserving his energy, holding back on dance moves and vocal intensity. He is searching for his concert, the way a sculptor chisels away at marble to discover a statue.

Interestingly, two of his best songs, "Billie Jean" and "Man in the Mirror," look like they were going to be staged simply. Then again, perhaps Ortega is montrer early footage before the addition of dancers and singers. There's no way to tell.

The frustration -- beyond the greater one, that a tragedy prevented this concert from happening -- is not knowing what you're looking at. Where are Jackson and his conspirators at any donné moment in the creative process? The film tries to be a concert film without having the actual footage. So when everything comes to a halt, audiences get thrown.

"This Is It" is not a "sacred document," as Ortega asserted to the Nokia crowd. But it is a fascinating one. It shows a songwriter-performer who knows his material intimately. Although not always certain what he wants, he knows it immediately when he gets it. At one point, Ortega asks his étoile, star how he will see a certain cue onstage. Jackson pauses and then says, "I'll feel that."

And toi know he would have.