Michael Jackson made a posthumous curtain call for legions of fans worldwide, as a movie charting the tragic pop icon's rehearsals for his concert comeback premiered across the globe.

Four months after Jackson's sudden death, red carpets were rolled out for 18 simultaneous screenings on five continents for "This Is It," a documentary culled from more than 100 hours of never-before-seen rehearsal footage.

Jackson family members and celebrities descended on a gala red carpet at the Nokia Theater in Los Angeles for the movie premiere which had been hyped as the last-ever performance by the "King of Pop."

The Los Angeles premiere got underway as vast swathes of the city were plunged into darkness by power outages caused by powerful winds.

"I've seen the movie three times and it's been emotional at every screening," Jackson's former manager Frank DiLeo told reporters.

"Sometimes I have to leave the room because I'm crying. But we're not going to cry tonight. Tonight is a celebration of Michael."

Gesturing to the gusts of wind buffeting the event, DiLeo joked: "He's happy. You can feel him spinning around in the air here... He's looking down right now laughing his read end off."

The Los Angeles screening mirrored events being held in Europe, Africa, Asia and South America before the movie makes its formal release on Wednesday.

Advance tickets in several countries sold out within days last month, as fans scrambled to be among the first to see a film billed by Sony s as the movie of "a concert that never happened."

Jackson, who died on June 25 aged 50, had spent the previous four months rehearsing in Los Angeles for a grueling series of 50 concert spectaculars scheduled to begin at London's 02 Arena in July.

More than 800,000 tickets had been sold for the concerts, with organizers promising one of the "most expensive and technically advanced" live shows ever.

Jackson was putting the finishing touches to the show at the time of his death, which authorities have ruled a homicide after coroners revealed that he had a lethal cocktail of six different drugs in his body.

Video footage from the rehearsals had been intended to help organizers critique the show and was never intended for public viewing. Sony bought the footage for 60 million dollars after executives saw only several minutes.

Analyst Jeff Bock of box office tracking firm Exhibitor Relations said the film could "play bigger than Elvis."

"This is more of a memorial than a movie," Bock told AFP.

The movie also got a stamp of approval from Jackson's long-time friend and confidante, actress Elizabeth Taylor, who was privy to a sneak preview.

Taylor, who recently underwent heart surgery, hailed the movie as the "single most brilliant piece of filmmaking I have ever seen" in a tweet on micro-blogging site Twitter.

"It cements forever Michael's genius in every aspect of creativity."

Despite the anticipation surrounding the film, a group of diehard Jackson fans have launched an online campaign urging devotees of the singer to boycott the movie, claiming it hides the truth about his final days.

The group claims on its website -- "This-Is-Not-It" -- that the movie attempts to mask Jackson's physical frailty as he maintained a punishing schedule of rehearsals.

"In the weeks leading up to Michael Jackson's death, while this footage was being shot, people around him knew that he looked like he might have died," the group said. "Those who stood to make a profit chose to ignore it."

Associates of Jackson have insisted the star was in good health during the rehearsals.