HBO is appealing a judge’s decision last month that sided with the Michael Jackson estate in its battle against the documentary “Leaving Neverland.”

The four-hour documentary details the allegations of Wade Robson and James Safechuck, who allege that Jackson sexually abused them when they were young boys. The film won the Emmy for best documentary or nonfiction special in September.

The Jackson estate has waged a high-stakes PR and legal battle against the film, suing HBO for $100 million and claiming that the subjects had a financial motive to lie. The estate sought to compel HBO into arbitration, claiming that the cable network was violating a 1992 contract for a Michael Jackson concert film which contained a non-disparagement provision.

HBO has argued that the documentary was protected by the First Amendment, and that the Jackson estate was seeking to chill public debate on child sexual abuse. HBO sought to dismiss the case under California’s anti-SLAPP statute, which prohibits frivolous suits that threaten free speech on matters of public concern.

In his ruling last month, Wu found that the anti-SLAPP statute does not apply to arbitration requests. He denied the motion to strike the suit, and ordered the case to arbitration. Wu acknowledged that his ruling would likely be appealed.

HBO filed a notice on Monday that it would appeal the ruling to the 9th Circuit Court of Appeal.

John Branca, the attorney who is co-executor of the Jackson estate, called the move a “cover-up.”

“If HBO truly believed that their desperate attempt to grab ratings was true, accurate, and fair, they would not be so strenuously avoiding a public reckoning of this junk programming which has become known as the Lies of Leaving Neverland,” Branca said in a statement. “The agenda is set at the top. Stockholders are questioning HBO’s leadership.”

Howard Weitzman, an attorney for the estate, said the appeal was a frivolous attempt to avoid the inevitable.

“Soon there will be a hearing, as the Court ordered, and damages will be awarded for HBO’s intentional and unlawful conduct,” he said. “The real questions are what is HBO afraid of and how much will they end up paying the Estate of Michael Jackson.”

HBO declined to comment.