The "devasting and disturbing" film has been shown at The Sundance Film festival in Utah, America.
It focuses on two men who claim Michael Jackson had abused them as children.
His estate deny the claims saying it's "an outrageous and pathetic attempt to exploit and cash in" on the singer, who died in 2009.
USA Today reporter Patrick Ryan was at the world premiere on Friday.
Wade Robson and James Safechuck say they were aged seven and 10 when the singer befriended them and their families.
Now in their 30s, they claim they were sexually abused by Michael Jackson.
He always denied the allegations when he was alive.
Police raided his Neverland Ranch in California in 2003 while investigating claims he had molested a 13-year-old boy.
The case went to trial and Wade Robson was a main witness for him. He said under oath that the singer never abused him and Michael Jackson was acquitted of all charges in 2005.
Since then Wade Robson has become a father and in an interview he said after two nervous breakdowns he finally revealed to his therapist the dark secret he'd been hiding.
"It was just pain and disgust and anger, the idea something like that could happen to my son."
In 2013 he filed a lawsuit against Michael Jackson's estate claiming he had been sexually abused by the singer, but a judge ruled he'd waited too long to seek legal action.
'Credible filmmaking'
The two-part film is directed by Dan Reed and the synopsis reads: "Through gut-wrenching interviews with the now-adult men and their families, Leaving Neverland crafts a portrait of sustained exploitation and deception."
Reporter Adam B Vary watched it and posted afterwards: "A deeply emotional Wade Robson and James Safechuck receive a standing ovation after the screening of Leaving Neverland. There will be a lot to say later, but I can say this: This is a thorough, devastating, deeply credible piece of filmmaking."
Kenneth Turan, the LA Times film critic posted: "A #sundancefilmfestival first: introducing the screening of the disturbing "Leaving Neverland" Michael Jackson documentary, fest topper John Cooper announced "there will be health care professionals" in the Egyptian Theater lobby if needed. This is one intense film."
And film critic for US Weekly Mara Reinstein put: "Shaking. Wow. We were all wrong when we cheered for Michael Jackson."
Because of Wade Robson and James Safechuck's previous support of Michael Jackson and claims that he never molested them, his fans have asked the festival to pull it, while his own estate has hit back at the project in a statement: "The film takes uncorroborated allegations that supposedly happened 20 years ago and treats them as fact.
"The two accusers testified under oath that these events never occurred. They have provided no independent evidence and absolutely no proof in support of their accusations, which means the entire film hinges solely on the word of two perjurers."
They go on to say that because the filmmaker purposefully decided not to interview anyone else other than the two men and their families he "neglected fact checking so he could craft a narrative so blatantly one-sided that viewers never get anything close to a balanced portrait."
The documentary will be shown on Channel 4 in Spring 2019.
Michael Jackson always denied any abuse allegations while he was alive.
He died on 25 June 2009 aged 50 after receiving a lethal dose of the anaesthetic propofol.
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