This was one brutal baby-sitting job, according to a new lawsuit.

A live-in nanny who watched over the daughter of a Park Avenue socialite and a celebrity surgeon claims she was scalded with boiling water, plied with drugs to increase her productivity, forced to wear sexy outfits, and pushed to attend Kabbalah classes and date her boss’ friends.

Andrea Duncan, 31, says she was turned into a virtual “slave” in the $8 million Carnegie Hill apartment — all for $250 a week, plus room and board, according to a lawsuit filed Friday by her high-profile attorney Rosemary Arnold.

“Working for these people was awful,” Duncan said. “They treated me worse than Cinderella.”

Duncan claims that Suzanne O’Leary, her 20-something ward, flew into an unprovoked, screaming rage in August and tossed a pot of boiling water at her, burning her abdomen, according to court papers.

But socialite mom Susan O’Leary forbade the nanny from seeking medical treatment, the suit alleges. Instead she offered this advice: “Take more Adderall, drink wine and apply aloe.”

Susan O’Leary threatened to fire her if she didn’t keep her mouth shut about the injuries, the suit alleges.

The untreated burn “permanently disfigured” Duncan, the Manhattan Supreme Court lawsuit says.

Suzanne O’Leary had been hospitalized for “severe emotional disorders” and had just been released from inpatient treatment when Duncan was hired, the lawsuit alleges. “But Susan O’Leary never told [Duncan] that,” Arnold said.

Susan O’Leary ordered the nanny to go on dates with her personal trainer and broker and to be “nice and accommodating to them” or be fired, according to the suit.

After Susan O’Leary fired her cleaning lady, she insisted Duncan pick up the slack — with no extra pay for tidying the 12-room apartment, the suit says. And when O’Leary hosted cocktail parties, she wanted Duncan scantily clad in a short white shirt and black tights.

She also wanted Duncan to attend Kabbalah classes with her, but the nanny, a practicing Buddhist, said no.

O’Leary eventually did fire Duncan after six weeks, and the stated reason was Duncan “exposing” herself outside the apartment, according to Arnold.

But Duncan, who has since returned to Ohio, was simply wearing a loose dress so that her stomach burns did not become irritated by the fabric, the lawyer said.

The real reason for the firing, according to court papers, was that Duncan “refused to be prostituted out.”

Dr. Patrick O’Leary, a spinal surgeon at the Hospital for Special Surgery in Manhattan, was not living with his wife and daughter and is not a defendant in the suit. He declined to comment.

When called by The Post, Susan O’Leary hung up.