Is it important for entertainment journalists to write nice things about movie stars? Do they even read their own press? Or are they so much in their own world that they just let their publicists tell them what’s going on in the world.

Once, Warren Beatty, whom I do consider the smartest guy in Hollywood, told me: “The biggest mistake you can make is to think no one’s reading what you write.”

But that’s Warren, he’s in a different league, and he knows everything going on around him.

Not so Julia Roberts, apparently. Mother now of three kids, she probably doesn’t have the time to read anything. She certainly doesn’t read this column. When she saw me last night at the premiere of her sleek new thriller, “Duplicity,” Roberts didn’t hesitate to cut me dead. She was rude, downright nasty, and dismissive. She snubbed me in front of other people to make her point, and later cut in between me and director Tony Gilroy to make her point. Her behavior was unexpected and chilling.

So what was the problem? Her officious publicist, Marcy Engelman, said: “She knows you broke the embargo on her play and wrote bad things about her.”

Indeed, a top agent at the party said, “Julia said, 'that’s the man who writes bad things about me.'”

Wait: you’re thinking, even if that were true, would a gracious person do such a thing in public? That’s something to consider.

In any case, another producer, a long time friend of Julia’s, then proceeded to tell me she’d absolutely remembered me writing something terrible about Roberts. “I know you did,” she said.

I was stunned. For the record: When Roberts was a week away from opening in “Three Days of Rain” on Broadway in April 2006, she was getting terrible advance buzz in the local newspapers. The gossip snipes said she looked bad, and couldn’t act. As an ardent fan of Roberts, I thought I’d go over and see what was happening. After mentioning the enthusiastic audience and the celebrities who’d already come to see her, I wrote:

“As for Julia: She was very good on Saturday afternoon. We heard her clearly in the last row. She has a strong stage presence and I suspect it will just get better and better as she warms up for opening night. She is funny and charming when appropriate, somber and grim with conviction too. She has all her lines digested and you cannot take your eyes off of her. She actually injects some life into that first-act character with some real Roberts sarcasm. It's most welcome. In the second act, though, she combines her best riffs from her performances in "Steel Magnolias" and "Ready to Wear," among others.

And she does not look thin, gaunt or unhappy. Quite to the contrary, she has a supple energy. Our audience went wild for her, with a standing ovation and cheering. So there.

As our usher said, she's already very good and by opening night, pow!

So retract those claws, kitties. And get ready. No, she's not Cherry Jones or Phylicia Rashad — yet. But she's a movie star and can act circles around anyone, and she's going to be a sensation in the papers on the morning of April 20.

My guess is this will open the door for her to alternate doing plays and movies, and that can only be a good thing.”

This may be the ultimate example of ‘a good turn will not go unpunished.’

Most reviewers, in fact, did not care for Roberts when the play opened. She got creamed by the regular theater critics. The morning after opening night I wrote:

“If anything, she seemed more relaxed on stage this time around, and significantly improved. It will be interesting to go see her at the end of the run in June ... When Roberts returns to Broadway in a couple of years — which she will undoubtedly do — I hope it’s in a romantic comedy or a farce where she can show off her real talents.”

I did think Roberts was brave to take on Broadway. And the fact is, the material was not suited to her. In the end, it may have been the same case that plagues many Hollywood stars who want to jump into the deep end on Broadway before learning to swim. Sometimes it’s better to do what Katie Holmes did in “All My Sons” this last year, and take a secondary role.

In any case, I wouldn’t have thought that what I wrote about Roberts in her play could have justified the scene at last night’s party. It was not pretty, and it was meant to be devastating. Her associates said, “This is what she was told.” And that’s even worse: to think that most people in Hollywood start many conversations with these words: “I was told you wrote (blank).”

Maybe it’s time to start getting better information.

As for “Duplicity”: Tony Gilroy is a great director. His “Michael Clayton” was superb. “Duplicity” looks terrific and moves effortlessly, even though the screenplay is often hard to follow. At one point, the characters arrive in Rome and no one knows what they’re doing there. But it looks splendid!

Gilroy brings along some of his fine “Michael Clayton” actors like Tom Wilkinson and Denis O’Hare. Paul Giamatti is spot on a crazy corporate chief. He replaced Billy Bob Thornton in the role, who was announced and then dropped out. I’m sure there’s a good story there.

“Duplicity,” if you can stick with it, concerns itself with corporate espionage. Clive Owen is perfect as a deadbeat spy who basically turns to a life of crime just because he can. Owen just gets better and better with every new movie. And Julia Roberts? Well, despite her misplaced anger towards this column, she’s a movie star. You can’t deny it. And even if the movie doesn’t always work, it’s nice to see big movie stars on the silver screen in a big studio movie with sumptuous locales and beautiful Italian hotel rooms.

My advice to Julia: get a new publicist, and a clipping service.