Angry Michael Jackson fans have launched an online protest about the singer's posthumous concert movie, claiming the film hides the truth about the "King of Pop's" tragic last days.

Fans claim "This Is It" -- which utilizes more than 100 hours of unseen footage of Jackson rehearsing for his concert comeback -- offers a distorted view of the singer's condition before his death on June 25.

The eagerly awaited documentary makes its premiere on Tuesday, screening simultaneously in 18 countries before going on a limited two-week release.

However a group of Jackson devotees are protesting the film on their website "This-Is-Not-It", claiming that the movie gives a misleading image of the singer, reported to have been in frail health before his sudden death.

- The true state of Michael Jackson’s failing health was being hidden from you by those who are making a profit from the screening of the 'This is It' movie - the group said in a statement.

The statement accused Jackson's advisors of ignoring the singer's ill-health while he participated in gruelling rehearsals for a 50-date series of concerts in London due to have begun in July.

- 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 singer was in good health during the concert rehearsals.

Authorities in Los Angeles have declared the singer's death a homicide and revealed in August the star had a lethal cocktail of six different drugs in his body when he died.