UTAH • A new four-hour documentary, Leaving Neverland, in which two accusers share stories of how they were sexually abused as children by the late pop singer Michael Jackson, sent shock waves through the Sundance Film Festival at its premiere last Friday.

The claims made by Mr Wade Robson and Mr James Safechuck are a matter of public record, as both men were involved in multiple lawsuits brought against Jackson's companies beginning in 2013. (The cases were later dismissed for being outside the statute of limitations.)

Directed by Bafta winner Dan Reed, the documentary - set to be shown in two two-hour parts on HBO - details the extent of the abuse with explicit and graphic accounts. It also describes how both of them were groomed, then abused, in their childhood.

Their stories have a similar thread: Both were younger than 10 when they first encountered Jackson, both were abused for an extended period of time and both had star-struck mothers who were unaware of what was going on.

Mr Robson accused Jackson of repeated sexual abuse when he was between the ages of seven and 14.

He developed strong fandom for Jackson at a young age, his "walls plastered" with posters, said yesterday's report in The Guardian about the documentary.

Mr Robson met Jackson at the age of five after winning a contest emulating the singer's dance moves.

When they were alone, he and Jackson allegedly engaged in a number of sexual activities, the report added.

Mr Safechuck alleged that he was sexually abused from the time he was 10 until he hit puberty. He met Jackson after clinching a role in a Pepsi advertisement and similarly developed a friendship, accompanying Jackson on tour.

Their friendship was said to have turned sexual when they were left alone by the child's unaware mother and allowed to share hotel rooms. Jackson allegedly introduced him to masturbation, which was seen as a form of "bonding", The Guardian's report added.

Mr Safechuck recalled that Jackson said he had performed oral sex on him while he was asleep. He also told the boy that he was Jackson's first sexual experience and that it was an "acceptable way of experiencing your love", the report said.

In a statement before the Sundance premiere, the Jackson estate declared: "This is yet another lurid production in an outrageous and pathetic attempt to exploit and cash in on Michael Jackson."

The estate has not responded to a request for comment after the premiere.

Because both men initially testified on Jackson's behalf when he was accused of sexual abuse in 1993 - saying that they never had any sexual experiences with the singer (Mr Robson repeated that when he testified again in 2005 at Jackson's trial in Santa Barbara County) - their credibility has come under heavy scrutiny from Jackson's fans.

The documentary explains at some length not only why both men originally defended Jackson, but what made them go public with their accusations when they did.

In an emotional question-and-answer session after the packed screening, director Reed discussed the process of getting Mr Robson and Mr Safechuck to open up for extensive on-camera interviews.

Mr Robson and Mr Safechuck, who were at the screening, were visibly moved by an applauding crowd and discussed their motivations for taking part in the project.

At the time that both men made their court filings, Mr Reed said he saw that "it might mean for the first time, someone might be able to tell the story of what actually happened" between Jackson and young boys.

Mr Robson and Mr Safechuck said they had been trying to communicate with each other for years. But during the legal process, they were forbidden to discuss the details of what had happened.

Both did not receive compensation for appearing in the documentary. "From the get-go, there was no money ever offered and we never expected anything," Mr Safechuck said.

"It was really trying to tell the story and shine a light on it. To give people (who have survived abuse) the same connection and comfort we've got going through this," he said.

"We've been looking for a platform to be able to tell the truth," Mr Robson said. "This film was nothing we ever thought about or sought out. It came to us individually."

Mr Robson and Mr Safechuck said they hoped the film would have a positive effect on sexual abuse survivors.

"We can't change what happened to us," Mr Robson said. "We can't do anything about stopping Michael. He's dead. That's gone. What happened, happened. The feeling is, 'What can we do now?' Hopefully, it helps other survivors feel less isolated."

DPA