So, guess who’s horse farm shopping. Think. Think of a useless middle- age female who’s decided to have purpose. Think that instead of this person’s boring high life and social life and meaningless life of hair appointments, manicures, facials, globe-trotting, fashion-trotting and fund-raisers for endangered yaks in the Andes, she now pines for simplicity and sod and turf and haylofts and buckets of oats and blacksmiths and stables and bridles and saddles and vets and wide-open spaces and the wind and the rain in her carefully highlighted long long hair.

Guess.

You’ll never guess.

Diandra Douglas. Mother of convicted drug dealer Cameron Douglas.

Must be she’s into housing. Now that her kid’s got a roof over his head and is safely tucked away in the can for five years, she has within only days of his incarceration — turned to herself. Surprise! Surprise! Those who know her say there’s never been anyone else in her life.

So what’s she doing these days? Since her family life is proof she blows it with humans, she’s now into animals. The four-legged kind.

The woman and her sister are in her Range Rover driving all over upstate Millbrook checking out the neighborhood which is so tony and highbrow nobody around even believes that in the old days anyone as low-class as George Washington ever slept in the vicinity.

She’s gone back four times to one place. Thirty acres. In the $3 million to $4 million range. Owned by a woman who’s had it on the market a while.

And she drives right up to people’s front doors. Strangers. And rings their bell.

One gentleman, so elegant he probably has suede patches on his gums, said: “Who are you? Why are you here?” She said: “You don’t recognize me?” He said, “No.” She identified herself as “I’m the person the New York Post threw under the bus. They say I was a terrible parent.”

More than a stranger house-owner needed to know, he thanked her for the drop-in and shut his 19th century door.

This is to let Liam Neeson know, she said: “I hear he lives in the neighborhood. I intend to drop in on him.”

SUNDAY is Mother’s Day. Jeremy Piven sent me this note:

“I was lucky enough to climb onstage with my mother at 8 years old. I believe I butchered Chekhov’s ‘The Darling,’ and she soared as usual. She runs ‘The Piven Theater’ to this day and is a straight shooter and a true artist and amazing mom. We need to tell our moms how much they mean to us as often as we can, and, on that note, words can’t describe how lucky I am to have Joyce Piven as my mom.”

So I called him.

“My mother has a specific sense of style,” he said. “Dresses in black. Black sunglasses.

“We were gypsies. Artists. But I felt we had a normal family. She was a terribly invested mother. Like if my school marks weren’t good, I’d be punished. I’d have to spend private time. And I wasn’t great in school then. I was a late bloomer.

“After school there’d be football. If our side won, all the rest of the kids went to celebrate. My parents made me go to Jewish school. I could never understand why I had to go.”

Does mom still work with her big star son now?

“Yes. And gives it to me straight. When we began ‘Entourage,’ I took her to an advance screening. My character swears a lot. Says terrible things. Another parent would be taken aback. She breaks through it all and just sees the character. She just sees the work.

“And she’s the greatest to run lines with. She’s so good, I get spoiled.

“And with my mother, it’s not the present. It’s about the thoughts we write on our card.”

SOUTHAMPTON is getting a new out post. Organic Avenue. Organic cold- pressed detox cleansing juice joint — whatever all that is — and they swear Gwyneth goes and Naomi Watts goes. OK by me. I couldn’t care less. I’m not going . . . You know a hotel joint in Hell’s Kitchen called Ink48? Well, Adam Lambert, Ke$ha, Jesse McCarthy, Jude Law were all recently there. Not together . . . Christopher Cox, Richard Nixon’s grandson, son of Tricia Nixon and state GOP chair Ed Cox, and his engagement to Andrea Catsimatidis (oh, so many names), daughter of grocery store emperor John Catsimatidis, are helpful to the GOP. Papa John just bought 10 tables at their annual June fund-raiser. The Greeks come bearing gifts.

NEW York is big with franks. Not those in hot dog carts. It’s Sinatra Week on “American Idol,” Frank Jr.‘s in town for “The Legacy of Sinatra Birthday Gala” and another Frank, Valli, just met Junior at Patsy’s when he was inducted into Jersey’s Hall of Fame . . . D. Paterson, all smiles, doing late-night Puerto Rican food churrasco, skirt steak with Sen. Majority Leader John Sampson on E. 57th.

PLEASE don’t pester me about an Only in New York. I had a great one. I can’t remember it. Leave me alone.