Enough with “The Great Gatsby’s” great p.r. It’s probably even getting screenings in basements in Bulgaria.

Director Baz Luhrmann’s costume- designer wife, Catherine Martin, on researching the ’20s-era wardrobe: “Although it’s a period piece, we wanted New York to look incredibly modern in those days. I studied in the Metropolitan Museum library, Fashion Institute library, Condé Nast library, digital libraries, sketches, old magazines, videos, a slew of books, online resources, which are prodigious and a wealth of information. Took me four years.”

At one showing, David Schwimmer schwam by Europe’s high priestess fashion journalist Suzy Menkes “here for the Met Ball and dying to see this movie’s clothes.” Schwimmer was tieless. And designer Prabal Gurung, in a green and white football outfit, led a squad of equally outfitted quarterbacks.

Not there for the wardrobe, Oliver Stone said: “I’m not going to sit and redirect it. I look forward to watching this. I read the book many years ago.”

David Koch: “We all know the book. ‘Gatsby’ is a great slice of Americana. I remember those old days of living that big fast partying life — of course, that’s before I met my gorgeous Julia.” Added gorgeous Julia, whose gorgeous outfit was gorgeous: “Our 17th wedding anniversary’s coming up.”

Michael Kors, who knows from making dresses and handbags: “I just gave $5 million to God’s Love We Deliver. They’re putting up a SoHo building, which might be named for me. Not bad considering I’m a guy who can’t cook.”

Among the crowd of young ’uns — guys with drawers below their belly buttons, females with skirts above — came Silas and Celia Chou. Billionaire Mr. Chou is the money behind Michael Kors. Mrs. Chou’s bag, however, was Chanel.

Through the scrum at MoMA’s private theater, publicist Peggy Siegal pushed me through some private door into some elevator to some private cubicle on some floor, where leading lady Carey Mulligan was sequestered.

Carey: “I’m wearing a black tux by Lanvin. I’m obsessed with it. I don’t own it yet, but I plan to. I’m afraid I now must think what I’ll wear with it.”

Besides her fashion fear was her fear of this huge movie: “It’s my biggest film so far. I was nervous how to handle it. I worried about playing the character. Anticipation’s the worst because I felt daunted by the role. How do you play her?

“And there’s the 3-D aspect. I felt no particular difference while making it, but to see the monitor afterward we had to put on those glasses, which were being held with big sticks.

“I’ve already seen the completed movie once. Difficult to see yourself blown up so big on this large screen. I can’t bear looking at myself. Others in my position probably have the same reaction at times. It’s awful. Difficult for me to watch me. You catch all sorts of imperfections. I kind of slouch down and hug my knees so I don’t stare too closely. I pop back up out of my seat a bit more when others are on-screen.”

Australia’s Baz Luhrmann lives in New York but filmed this in Australia: “I’m from the West. So a little farther west from LA — like a long way west — and there’s Australia. We have homes both places. My kids go to school in both places. This is their adopted home. Australia’s the roots, America’s the wings.

“We shot there because it’s cheaper. Also our longtime collaborators are there. Problems were remaking that terrain — where there’s no deciduous trees — into Long Island. But we did make use of what we had. Like my old Christian Brothers college became Gatsby’s mansion.”

MAY 22, Christie’s, Hillary Clinton gets the Helen Keller Humanitarian Award . . . Tommy Lee Jones directing “Homesman,” Producer Peter Brant calls it a woman’s story. A Western. About pioneers finding it tough adapting to the rootin’, tootin’, shootin’ Wild West. Filming’s down to the last 12 days in New Mexico. We get the movie come springtime.

SATURDAY at Ellis Island its Medals of Honor for Mia Farrow, Dionne Warwick, Rep. Peter King . . . More hotels coming up. Ian Schrager doing one in Madison Avenue’s Clock Tower building. Opens 2015. And the Tao Group’s building in the Maritime Hotel on 16th and Ninth . . . Matthew McConaughey’s all-time favorite film? Paul Newman’s 1963 “Hud.” McConaughey even had a Lab dog named Hud.

JUST a thought. So many teachers accused of having sex with teenage students. Times have changed. In my day, kids had to be satisfied with just banging the erasers.

REMEMBER Hollywood p.r. Ronni Chasen who in 2010 was killed in her car? Ed Asner is to narrate the documentary “6:38: The Death of Ronni Chasen.” LAPD spent six months investigating and sifting through 150,000 pieces of evidence yet Ryan Katzenbach, doing this project, claims he’s discovered “shocking contradictions in investigating the murder.”

SATURDAY afternoon. Belmont. Eighth race. 4-1 shot. Horse No. 5. “Gossip Columnist.” At the track my assistant Molly — who obviously has nothing better to do — placed a bet. She won $3.20. May my vast importance and incredible power be known.

Only in New York, kids, only in New York.