FOR A WHILE last summer, it was the hottest T-shirt in Hollywood. "New York, New York," it said, over a picture of Liza Minnelli singing and Robert DeNiro playing the sax in a scene from the film then being shot on the MGM lot.

Hey, what a T-shirt. What a status symbol. It meant you were working on the film, and this was to be some film. Martin Scorsese, hot, young, short director, working with two superstars on a love story shot like a classic movie musical against the background of the big band ear.

Bernardo Bertolucci visited the set. Ingmar Bergman visited the set. Vincente Minnelli visited the set. Every director then working on the lot came to watch when they filmed the big show-piece production number, "Happy Endings."

Now it is one summer later."New York, New York" is finally complete and in release. And United Artists, at a big press hoo-hah in New York last week handed out brand-new T-shirts to reporters flown in from around the East.

But it wasn't the same T-shirt. It was a different design. It didn't look so classy.

This T-shirt wouldn't get you a cup of coffee at Schwab's.

Funny how things can change. Razzmatazz

YEAH, THIS WAS going to be some movie. Just like in the old days. The good ones. Razzle-dazzle, razzmatazz, jazz and pizzazz. Everybody working on it was up, up, up.

But then shooting started to drag on, on, on. As recently as April, Scorsese was back on the soundstages reshooting scenes. Plans to do location shooting in New York were scuttled for economic reasons, even though the Waldorf-Astoria had pledged cooperation as a site. A Pasadena hotel was used instead.

"New York" started creeping past its budget and was $2.5 million over by the time it was finished for $8.7 million. Executives at United Artists were reportedly getting edgy. Delays followed delays, rewrites followed rewrites, and they began to wonder if all this hullabaloo would be worth it. They were having grave, meaning "money," doubts.

Here's where the Hollywood happy ending should come in - the executives rebuffed; the film a smash; the critics overjoyed; the public beside itself with indescribable ecstasy.

But you know, sometimes even executives turn out to be right. 'Happy Endings'

LIZA MINNELLI used her mother's old dressing room, her mother's old hairdresser (Sidney Guilaroff) and strutted her stuff on her mother's old MGM soundstages when making "New York, New York."

Her mother was Judy Garland.

And at last week's press conference in New York, Liza sounded flustery and hesistant the way her mother used to sound in dramatic scenes on the silver screen: lots of "Well, uh, I - " and "Oh, uh, I - " and arm waving and searching for words. It gets a little creepy sometimes. But she perked up when talking about the big number, "Happy Endings," the one that became a legend even as it was being filmed.

"The first thing we did was that production number and we had, we had a wonderful time," said Minnelli, sitting behind a table with De Niro, who was 15 minutes late, Scorsese and coproducer Irwin Winkler. "We didn't know how the movie was going to turn out because that number was the first thing that was shot.

"But it was extraordinary because all of the people who worked at Metro so long and are still ther - the grips, the people I'd known all my life - all came to watch this production number. It was, oh, it had a wonderful feeling about it. It was like Metro come alive again for two weeks."

And the "Happy Endings" number itself was a lulu, a 12-minute super showstopper that merrily spoofed movie musical conventions (including the heavenly chorus) and began with Minnelli as an usherette at a movie palace shinning a flashlight on her face like a spotlight and singing:

"Happy endings, far as I can see - are only for the stars, not in the stars, for me."

The ensuing romp recalled mama's big "Born in a Trunk" number from the 1954 "A Star Is Born" and featured a cameo appearance - as a betuxed emcee at an oldtimey mike - by Minnelli's father-in-law, Jack Haley Sr., who played the Tin man in "The Wizard of Oz." With mama.

After principal photography was completed on the whole film last August, there was a special screening of roughty edited footage, about 40 minutes' worth, for the members of the crew who'd been called upon to wreak wonders once commonplace in the big studio era but now much harder to bring off - glittery sets, huge indoor crowd scenes, swooping crane shots. The crowd was deliriously demonstrative over its own work, with most of the enthusiasm going to "Happy Endings," and justifiably so. It was the old magic at work again. It was a knockout.

The number has been removed from the finished film.

Jack Haley Sr. lies on a cutting room floor.

The 12 minutes of magic has been levelled to less than three.

Funny how things can change. Sneak Previews

WINKLER, WHO dictated how long the finished picture could be (it is still two hours and 32 minutes), defended this enormous deletion at the press conference. "We wanted to tell a story about the relatioship between two people," he said. "It was not proper if we went off on a tangent for 12 minutes." He denied a rumor that the sequence cost $1.2 million all by itself.

"How much did it cost?" Minnelli asked him.

"It cost about $350,000," he replied.

At a sneak preview in New York, the audience lit up for even the smidgen of the number that remains. They seemed to be growing weary, anyway, of the repeated spats and reconciliations between the Minnelli and De Niro characters - a rising big band singer and the seemingly psychotic saxophone player she inexplicably loves.

Winkler was asked about the wisdom of ejecting such an apparent crowd-pleaser from the film. He said that eventually "Happy Endings" might be released as a short film on its won. That would be commercially unprecedented, by the way. Then he said it might be reinstated when the film is sold to television "in five or 10 years." Or two or three. Finally he said, "We wanted to tell a story about people, so we ahd a choice between, really, a marvelous entertainment and a story about people.

"And we decided to tell a story about people." A Favorite Deleted

NEW YORK, New York" may be one of the largest-budget movies ever shot with a script that was largely a rumor. Though credited to Earl Mac Rauch and Mardik Martin, everybody and his wife got into the writing act, including Scorsese's wife Julia Cameron. Saxophone consultant Georgie Auld claimed in an interview to have written "95 per cent" of De Niro's dialogue as well as coaching him on the horn.

Socrsese sought counsel everywhere. Musical numbers didn't really come and go; they tended just to go. "We had a number called 'South America, Take It Away,' a favorite of mine, that was very funny, but that's been deleted," Scorsese noted. Songs by actress-singer Mary Kay Place (Loretta of "Mary Hartman, Mary Hartman") have been thrown out or radically shortened because - according to one reliable industry insider - an ex-film critic corny of Scorsese's looked at Place's footage and claimed she would "ruin the picture."

Another famour movie critic, asked for help when Scorsese couldn't come up with a satisfactory ending, looked at the film, was reportedly "appalled," and fled.

On the set, an impromptu attitude, to put it mildly, prevailed. Some might call it anarchy. "I think back and I don't know hoany of us survived it," said Minnelli. "The energy level that went on was just incredible, and my own energy level isn't exactly zilch as you know. This is the only movie I can remember making where I can't remember ever sitting down. It was like a whirlwind."

The script was written communally as they went along.

"It got to the point where everybody was running around with these little tape recorders saying, 'What was that?' (She pretended to be holding up a little tape recorder.) 'Say that, that!' It was incredible! Incredible!"

Scorsese hastily intervened. "The movie wasn't written on tape recorders," he said, somewhat nervously. "Everything's naturally structured and worked on. We would structure the ideas we put into the tape recorders."

At any rate, there was extensive rewriting on the set, and that means delays, and that costs money. Creative Collaboration

IN ONE SCENE, De Niro drags Minnelli off to a justice of the peace to get married. When she proves resistant to the idea at the judge's very doorstep, the De Niro character threatens to kill himself. Indeed, he lies on the ground with his head under the wheel of a taxicab and tells the driver to run over him.

That was De Niro's own idea, Scorsese said.

"When you get that kind of input, you can't say, 'No more ideas, I'm sorry, stop the ideas,'" Scorsese explained.He is known as the director who shoots more feet of film to get one scene than almost anybody else.

"So we shot the scene; we covered ourselves with the master shot so that we could cut the scene without Bobby putting his head under the wheel of the car, because we were concerned about the elements of farce, you know, farce turning into drama."

"Can I say something here?" asked Minnelli meekly.

"Sure," said Scorsese.

"Part of the fun of doing the film, was, well, a lot of these things that occur, I didn't know about it. Bobby and Marty would say, 'Well, we're just going to - well -' and I'd say, 'Well, what -' and they'd say 'Wait, you'll see -'"

"You did know at first," Scorsese corrected her. "But after the first two days, see, it was moving, so after that, we were full of surprises."

"And it's so funny, " Minnelli said to De Niro, "because I didn't know you were going to lie down under the car at all!" She gave out with a big giggle.

It became apparent as this chat went on that Minnelli was locked out or at least ignored when many of these inspired creative collaborations were transpiring. Scorsese kept saying things like, "Bobby and I discussed this" or "Bobby and I talked about the scene," or De Niro would say, "Marty and I" talked about this.

Minnelli seemed always to be the last to find out what was going to happen when the camera rolled.

Add to that the fact that De Niro's performance in the film is a virtual circus of horrors that seems bent on upstaging Minnelli, and that the character she plays is tolerant to the point of saintliness of De Niro's tantrums and rages, and it becomes ironic that producer Winkler proclaimed fortissimo early in the press conference, "This is one of the greatest feminist films ever made."

Asked about that, Minnelli would only say, later, "I don't know. I don't know. I'll leave that up to you." This Is a Tribute?

NIGHTTIME.Interior of a car. A lover's quarrel. No, a lover's brawl. Flapping and fluttering and socking and slapping. Minnelli is supposed to be pregnant, but she and De Niro go at it rambunctiously just the same. Screaming, crying, cursing, shouting, and finally Minnelli shrieks, "The baby! The boby!" and collapses in the back seat.

At this point during the sneak preview, one member of the audience turned to a companion and said, "This is Scorsese's tribute to the great old musicals?" DeNiro, the Musician

DE NIRO studied the saxophone fastidiously, perhaps fanatically, during the making of the film, so it wouldn't look like he was just faking it. Of course he is just faking it. But you've got to hand it to him in the persistence department. He bought an expensive sax and a tape recorder on which to practice. United Artists had to reimburse him for both, however, and expects them to be returned to the company.

Winkler recalled sentimentally at the press conference that De Niro once spent his own money to go to Italy and get in the right mood for a character he was playing in a low-budget picture for which "he wasn't even getting that much."

Since he has been consistently reticent about giving interviews, De Niro was the subject of considerable attention at the press meet. As he answered questions it became evident why it is just as well he doesn't give a lot of interviews.

Was it difficult, one woman asked, for him to adapt his "intense" acting style to the light comedy at the beginning of the film?

"No," said De Niro, "It's just that we tried stuff and I - I don't think that - Uh, repeat that again; I just want to make sure I got it right."

The question was repeated.

"No," said De Niro, "because I tried to imagine. There are certain kinds of things you can do that you think are funny and certain kinds of things that aren't funny."

And later he added, "Everybody just wanted to make a movie, you know, just do as good a job as we could. We all worked well together, we all got along, we had a good time, that's the main thing. That's the main thing." The Business of Art

WINKLER AND Scorcese are asked how the public will feel about a movie in which the male lead character is, as one early viewer put it, an "unrepenting jerk."

"I think he's an artist," says Winkler. "Not everybody in life that you meet is a Miss Goody Two-Shoes."

Scorsese, who often appears to be brooding behind his protective dark beard, says softly. "Who knows what any public will feel?"

A few minutes later, a United Artists publicist is on the telephone, apparently talking to The Coast, raving about the film and the reaction. He is dressed exactly as you might expect if you are slightly skeptical about people in the business end of the movie business and he is accompanied by a woman whose hair is a mushroom cloud of cotton candy.

He is shouting into the telephone and he sounds on the verge of hysteria, even though the press conference had been a pretty sleepy, sullen affair.

"It's a wonderful movie, Merton!" he says with all the gusto at his command. "AND THEY'RE LOSING THEIR HEADS OVER IT!"

Hooray for Hollywood. And happy endings.