Celebrity biographer Ian Halperin set out to take down Michael Jackson in his just-released unauthorized look at the late singer's life, "Unmasked: The Final Years of Michael Jackson." Instead, Halperin said he ended up writing a sympathetic look at a sad world inhabited by the King of Pop, in which he said Jackson was plagued by anorexia, crippling financial problems, a deadly lung disease, a torrid addiction to prescription medication, fears of mortality and, in his final months, a crippling anxiety that he could not pull off the proposed 50-date residency at the O2 arena in London, which would have kicked off Monday.

In light of Jackson's death, Halperin had to scramble over the past few weeks to update the book, which was originally slated for release July 7, the day the world paid tribute to Jackson at a memorial at the Staples Center in Los Angeles.

According to the author, those around Jackson feared the singer was not strong enough to complete the This Is It residency but forged ahead anyway, even after the 50-year-old performer reportedly collapsed during his second rehearsal for the shows due to unexplained causes.

"He was ill," Halperin told MTV News. "They were forcing him and urging him to come back with this O2 residency tour instead of really being by his side and getting proper attention, which is the saddest thing about his life."

The Canadian journalist is best known for a series of unauthorized celebrity biographies including "Who Killed Kurt Cobain? The Mysterious Death of an Icon," "Bad and Beautiful: Inside the Dazzling and Deadly World of Supermodels" and "Celine Dion: Behind the Fairytale - A Very, Very Unauthorized Biography." He's also behind the 2008 documentary "His Highness Hollywood," in which he went undercover as a gay actor to infiltrate the Hollywood audition process and the Church of Scientology. He writes in the Jackson book that the singer shed a startling amount of weight in the lead-up to the London shows, hardly eating any meals and leading his medical team to worry that he was developing anorexia. One unnamed staffer pegged the singer's recent weight at around 100 pounds, a very low figure for a man of his height, 5-foot-10.

"I disclosed that he was anorexic before he died, and one of the most serious side effects of anorexia is cardiac arrest," Halperin said, pointing to the coroner's report that cited cardiac arrest as a contributing factor to Jackson's death.

One of the most outrageous claims in the book — the first and quickest to hit shelves in the wake of Jackson's shocking death on June 25 — allegedly comes from one of Jackson's closest friends. The unnamed friend said that a month before Jackson died, he told his 11-year-old daughter, Paris, that he feared he only had weeks to live.

"He called her into his room and told her not to get mad at him if he didn't make it to Father's Day," the friend said, according to Halperin's book. "He had a premonition that his days were numbered. He felt extremely ill. Unfortunately, no one wanted to help him. His closest advisers tried to control him with medication, drugs and false hopes. They wanted to make sure he didn't bail on the O2 gigs and that they would not be paid the money Jackson owed them."

Halperin adamantly defended his use of anonymous sources by saying that everyone around Jackson — doctors, lawyers, friends and lovers — are made to sign confidentiality agreements.

According to this friend, in Jackson's final months, the pop star spent hours, sometimes days, in his room writing extensively. "I asked him if he was writing a novel. He replied, 'Just some thoughts on my journey on this earth. I want to leave something to my children,' " the friend recalled. Hearing that, the friend feared that Jackson — described as erratic and depressed during his final few weeks — could be suicidal.

After producers of the London shows pushed them back due to what they claimed were production issues, Jackson's mental and physical health continued to deteriorate, according to the book, with the singer getting increasingly "terrified" about the prospect of performing the gigs.

"He wasn't eating, he wasn't sleeping and when he did sleep, he had nightmares that he was going to be murdered," an unnamed source claims in the book. "He was deeply worried that he was going to disappoint his fans. He even said something that made me briefly think he was suicidal. He said he was worried that he was going to end up like Elvis [a comparison Lisa Marie Presley, Jackson's ex-wife and Elvis' daughter, made shortly after Jackson's death]. He was always comparing himself to Elvis as long as I knew him, but there was something in his tone that made me think that he wanted to die, he was tired of life. He gave up."

Though no one in the book claims to have seen Jackson use illegal drugs, several sources described his alleged longtime addiction to prescription pills. Halperin claims that after a 2003 "60 Minutes" interview, Jackson overdosed on prescription pills and had to be revived by a doctor.

In December, Halperin claimed Jackson was suffering from a genetic lung condition called Alpha-1 antitrypsin deficiency and that the singer would be dead within six months; Jackson died six months and one day later. The biographer once posed as a hairdresser in order to meet Jackson, for what was originally planned as a documentary on the singer. He said sources close to Jackson told him the singer was gravely ill and suffering from the lung disease but that Jackson's circle of advisers tried to quash Halperin's claims to keep the O2 dates on track.

Halperin said he originally set out to paint an unflattering portrait of Jackson, feeling that the singer had unfairly been acquitted on child-molestation charges in 2005, charges Halperin now believes were not true. "I set out to nail him after his acquittal. ... I was livid," Halperin said. "But I dug up a 1993 official court document that says Michael Jackson was forced [in a 1993 molestation allegation that ended in a settlement] by his insurance company to settle."

Again with no named sources who agreed to speak for attribution, among the other big bombshell claims in the book is Halperin's insistence that Jackson was a gay man. That revelation is based, Halperin said, on confirmation from some of the singer's alleged gay lovers, as well as footage of Jackson dressed as a woman. "I have photos of him disguised as a woman going to those meetings [with his lovers]," said Halperin, noting that the photos and other alleged proof of Jackson's sexuality will be included in the film, due next year, for which he claims to have shot 300 hours of footage.

A spokesperson for the Jackson family has not returned MTV News' repeated requests for comment.

For complete coverage of the life, career and passing of the legendary entertainer, visit "Michael Jackson Remembered."

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