The hottest new cast member of “The Real Housewives of New York” has a gut, chest hair and sweats at the mere sight of sun.

Meet John Mahdessian, owner of the Upper East Side’s high-end dry cleaner, Madame Paulette, and boyfriend of Dorinda Medley, “RHONY’s” latest unmarried addition.

Mahdessian is the show’s breakout star this year, thanks to his and Medley’s cantankerous relationship, his shameless flirting and his larger-than-life personality.

In one episode, the 49-year-old is caught grinding against Housewives Sonja Morgan and Kristen Taekman like a horny spring-breaker; in another, he’s partying it up solo, to everyone’s horror, at midtown’s Beautique.

Last week, Ramona Singer called Mahdessian “crass” and accused him of using her pal for her swank uptown pad and connections.

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But the so-called “Sultan of Stains” — who grew up in Little Neck, Queens, and is now the couture cleaner of choice for everyone from Anna Wintour to Lady Gaga — is unfazed by the attention, good and bad.

“It really doesn’t do anything for me because when I go to the Met Gala, the richest, most prominent people recognize me,” says Mahdessian, who keeps a pack of Marlboro Lights within reach.

“The higher up you go, the more I’m respected and recognized. In my own little world, being in the business for so many years and catering to the richest people, I’m used to that. It’s normal.”

Madame Paulette was opened in 1959 by Mahdessian’s father’s uncle, who wanted a local, fine dry cleaner to tend to the extravagant gowns of his wife, a French couturier named Madame Paulette. When Mahdessian’s father became ill, the Villanova grad waived an offer from Wall Street in order to take over the family business in 1987.

“I was able to develop methods and techniques that allow us to be leaders and pioneers now in our industry,” he says from his tiny, windowless office, its fridge stocked with bottles of Notorious Pink, the line of rosé his girlfriend is hawking.

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Mahdessian boasts that his clients include Cyndi Lauper, Gerard Butler, Jay Z — who needed his white tuxedo cleaned in under four hours for his 2012 appearance at Carnegie Hall — and former Mayor Michael Bloomberg. (“I always have the idea of getting together so we can keep Gotham City spotless,” he says. “He would fight the crime, and I would fight the grime.”)

But his No. 1 client right now is the 50-year-old Medley. “I get everything dry cleaned, including practically my underwear at this point,” says Medley, who, when she’s not on “RHONY,” is busy managing her estate and exploring what her rep calls “various business ventures.”

Mahdessian is more than a dry cleaner, she insists. He’s “the man,” as she gushed about him on the show. (Other words she’s used to describe him are “machismo” and “Mafia” — he did, after all, infamously arrange for a police escort for P. Diddy in 2011 so the tardy rapper could make it to a performance in New Jersey.)

When I go to the Met Gala, the richest, most prominent people recognize me. The higher up you go, the more I’m respected and recognized. - John Mahdessian, dry cleaner to the stars

Their relationship naturally kicked off with a Madame Paulette rescue story. In 2009, Medley and her second husband, hedge-fund honcho Richard Medley, were invited to a Prince’s Trust dinner at Buckingham Palace. Medley had borrowed a $65,000 Roberto Cavalli gown — only to have someone spill a glass of red wine on it.

“She, of course, got upset and freaked out,” says Mahdessian, who thereafter became friendly with Medley at the members-only Core club.

“One of her friends said, ‘Don’t worry about it, darling. Bring it to Madame Paulette and they’ll take excellent care of it.’ We made it look brand new.”

After Richard died in 2011, Medley and Mahdessian began dating.

The rest is reality-TV history.

But while broadcasting one’s relationship on Bravo normally spells disaster, Medley says the show has only strengthened their relationship.

“I think it’s helped John to also be more self-aware. Maybe what he thinks is funny, the public doesn’t,” says the Housewife, who called Mahdessian at least eight times during an hourlong interview. “I know John and love John and I know he’s harmless. But sometimes he can be a little bit too playful, I guess.”

While she refused to discuss whether marriage was on the way, Mahdessian was more forthcoming.

“I need to get a ring,” he says. “I know that I would have to raise the price of every piece of dry cleaning by $1 to get the rock she deserves.”

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