AceShowbiz - U.S. network bosses behind the damning "Leaving Neverland" documentary have fired back at Michael Jackson's estate officials, dismissing their $100 million (£76 million) lawsuit over the controversial series.

Executors for the King of Pop's estate filed suit against HBO executives in February in a bid to block plans to broadcast the damning four-hour feature, which centred on the long-running relationships the superstar shared with Wade Robson and James Safechuck when they were kids, during which they claim they were taken advantage of by the late singer.

Jackson's representatives accused producers of engaging in a "posthumous character assassination" of the "Thriller" icon, and alleged the documentary violated the terms of a series of non-disparagement agreements they signed with the musician back in 1992, when HBO chiefs aired a two-hour special, titled "Michael Jackson in Concert in Bucharest: The Dangerous Tour".

They argued the contracts cover periods both during and after the televised event.

Network officials pressed on with the "Leaving Neverland" premiere in early March, and now lawyers for HBO have responded to the breach of contract legal action, insisting the non-disparagement claims in the decades-old deal are "expired and entirely unrelated," according to The Hollywood Reporter.

The defendants argue the Jackson estate's entire case hinges on an old contract, which was fulfilled by all parties and therefore terminated, and insists there is no such clause in the deal which would mean HBO bosses are "bound for all time from doing anything that Mr. Jackson's posthumous representatives might consider, in their subjective opinion, to be disparaging".

They want the case to be tossed, but Jackson estate attorney Bryan Freedman vows, "HBO will be held responsible for its reprehensible conduct."

Jackson, who passed away in 2009, was previously acquitted in a 2005 trial for child molestation.