An alleged serial squatter has become a living nightmare for an Upper West Side couple — refusing to leave their condo after they put her up for what was supposed to be a short stay, a new lawsuit claims.

A friend of Celeste Champoux’s — a film producer who worked on 1988 B-movie “Senior Week” — told Nancy Hament and her husband Richard Scarola that his pal needed a spot to crash before her upcoming move to Hawaii, claims the Manhattan Supreme Court filing.

But more than a year later and Champoux is still living in the family’s spare studio apartment steps from the Museum of Natural History — while making threats and moving their property in the hallway of the posh pre-war seven-story building, according to the suit.

Now, Champoux — who has been sued at least two other times in eviction proceedings since 2014 — is demanding the couple pay her $25,000 if they want her to go, claims the suit, filed by Scarola, an attorney representing his wife in the matter.

Champoux’s attorney, however, said Tuesday the suit was bunk — and accused the “nasty” couple of committing “elder abuse” against his client and of cutting off electricity and water to the unit.

“You can’t just cut off essential services to intimate her to move,” her lawyer, Stephen C. Dachtera, told The Post.

The couple is not only suing Champoux, but also the friend who introduced them to the woman, accusing him of fraud for knowingly deceiving the pair by allegedly telling them she just needed somewhere to stay before her move to Hawaii.

Cinematographer John Corso, who also worked on “Senior Week,” “falsely represented that Champoux had a planned move to Hawaii and that her stay would be for a very short time,” the suit filed Monday claims.

The couple “agreed that she could stay in the Premises for a short time at a modest cost,” the suit claims, noting that the price didn’t even cover the maintenance for the studio unit, which is adjacent to their main apartment on a prime corner of West 81st Street and Columbus Avenue.

“Champoux acquired her occupancy of the Premises through fraud by Corso to plaintiff’s great and continuing damage,” the filing reads.

Both of Champoux’s previous eviction cases also involve Corso. Neither responded to requests for comment Tuesday.

In 2014, Champoux’s Upper East Side landlord began eviction proceedings against her for not paying the rent, though she says she was purposefully withholding payments due to a lack of repairs at her rent-stabilized apartment on East 87th Street.

Corso, according to court filings, tried to vouch for Champoux and claimed that he could cover her rent once “project funding” for a non-specific IMAX film was secured.

In total, Champoux paid less than $3,000 of the nearly $60,000 she owed.  After living there for 46 years, she was finally evicted in 2018.

Months later, she moved to the Soldiers, Sailors, Marines and Airmen’s Club in Midtown, where she claims she had an arrangement to provide marketing services for the discount servicemembers hotel in exchange for a free room. 

The attorney for the club claimed during a pre-trial hearing in February 2020 that Corso and Champoux “perpetrated a fraud” to get her a room by claiming the senior, who said her only income was a $125 monthly pension, was a marketing wiz.

“Our director fell for her story,” said Margaret Ann Harley, the secretary of the club’s board, “that she was a marketing expert, according to her friend, and this other gentleman,” a reference to Corso.

“And she was not a marketing expert at all. She… didn’t perform any duties and then we asked her to leave, and she wouldn’t leave,” Harley told the court.

Champoux, who claimed to be a former diplomat in that 2020 transcript, adding, “it’s not as if I just fell out of a coconut tree.”

She managed to ride a COVID hardship declaration and find a lawyer, only leaving in April 2023 after a $25,000 payout.

Champoux moved into the Upper West Side pad that summer, according to the couple’s suit.

Dachtera, Champoux, lawyer, told The Post that his client is infirm, barely capable of hearing, and that Corso is a dear friend who helps her out because of her difficulties. 

According to an article from 2012 in the now-defunct local news site DNAinfo, Champoux would now be nearly 80 years old.

Dachtera said he’d never heard about the Hawaii claims — and that they have no bearing on the case.

“The landlord is not allowed to subject her to and engage in elder abuse,” Dachtera told The Post, who claimed the couple cut off electricity, water and that Champoux doesn’t even have a key to the unit.

Hament and Scarola, a managing partner in boutique Manhattan law firm Scarola Zubatov Schaffzin PLLC, did not return messages Tuesday.