A new $20 million lawsuit blasts the KARDASHIANS for fooling America with their “scripted” and “fake” reality TV show – and the shocking court pa­pers also accuse matriarch KRIS JENNER of cheating, bullying and lying.

The sensational court papers, ob­tained by The ENQUIRER, blow the lid off the “shameful rewrit­ing of history by the Kardashian siblings, at the direction and behest of Kris Jenner” – calling her an “atrocious” mom to daughters Kim, Kourtney and Khloe.

Filed on the eve of Kris’ FOX net­work talk-show debut, the lawsuit claims to expose the real story behind “Keeping Up with the Kardashians.” It could even put the future of the franchise in jeopardy, according to one TV industry expert.

In damning documents, the 57-year-old family matriarch is described as “a manipulative and devious mother and ex-wife who simply used and exploited her children and family.”

The emotionally charged legal ac­tion – alleging defamation, harass­ment and conspiracy – was launched by Ellen Pearson-Kardashian. She’s the widow of the late O.J. Simpson attorney Robert Kardashian, who fathered Kim, Kourtney, Khloe and Rob with first wife Kris. In the court papers, Ellen asks the court for per­mission to file a counterclaim against a lawsuit filed that Kris and the Kar­dashian siblings filed against her.

Ellen also unloads on her former stepchildren in the blockbuster filing, saying they do not have “meaningful careers or professions” and instead “subsist on exposing their perverse private affairs to the world,” including “unorthodox sexual acts, extramarital affairs, sex tapes and out-of-wedlock child birth.” The widow was painted as the evil stepmom and sued by Kris and her daughters after she allowed diaries belonging to Robert – who died almost 10 years ago from throat cancer – to be published.

In her counterclaim, Ellen says the Kardashians showed her in a bad light in a Season 8 episode of their reality show. Ellen claims that the episode was cooked up as “damage control” after Robert’s journal “ex­posed” Kris. Robert portrayed her as a cold, uncaring mom who verbally and physically abused her daughters, was often absent and cheated on him.

“Ellen believes that the damage inflicted on her by Kris and the show is worth at least $20 mil­lion,” said an insider.

“She wants to really make them pay for what they’ve done to her. And it couldn’t come at a worse time for Kris – just when she was in final rehearsals for her talk show.”

One expert says that the lawsuit is bad news for the famous clan.

“The truth is that reality shows aren’t real,” TV analyst Stuart Eller told The ENQUIRER. “Situations are manipulated for the sake of tweaking the audience interest, but too much phony dramatics could alienate view­ers and put the entire Kardashian franchise at risk. This lawsuit could be another nail in the coffin for them.”

The famous family has fired back by publicly slamming Ellen for her “lies.”

And a rep for Kris Jenner previously said that she finds the accusa­tions against her “ridicu­lous” and “untrue.”