The dialogue sounds like something from "Dirty Harry": "If you gotta die for something, this sure as hell ain't it."

But this time Clint Eastwood is playing himself, holding up a tiny vial of raw cocaine known as "crack." And starting Friday, he'll be seen in that role on theater screens around the country, delivering a powerful antidrug message the motion picture industry hopes a billion people will see in the months ahead.

His costar in the public service announcement, one of 11 antidrug trailers featuring Hollywood stars, is First Lady Nancy Reagan.

"These trailers will reach millions of young people, and I'm sure they'll have an effect," she said yesterday at a White House theater premiere of the series.

The Eastwood-Reagan trailer will precede two soon-to-be released films, "Jaws, the Revenge" and "Superman IV: The Quest for Peace." It and the other 10, also paired with films appealing to particular audiences, were produced by Hollywood film tycoon Jerry Weintraub after Mrs. Reagan appealed to the film industry last fall for help in her antidrug campaign.

"This is the redemption of our pledge to the first lady," said Jack Valenti, president and chief executive officer of the Motion Picture Association of America (MPAA), voicing what he said is industrywide determination to erase "this deadly fungus on the face of the nation."

Weintraub, chairman and chief executive officer of the new Weintraub Entertainment Group, said if "just one person in the audience" is convinced to stay away from drugs "then all of our time and effort will have been worth it."

Dramatic in their starkness, the trailers open with a darkened screen that gradually reveals a solitary figure holding a vial of cocaine.

"See this cute little vial here. It's crack, raw cocaine, its most addictive form," Eastwood begins in his spot. "You think it's the glamor drug of the '80s? It could kill you. And if you gotta die for something this sure as hell ain't it."

Across the screen comes the warning that concludes each trailer: "Don't ever try it. The thrill can kill."

"I don't think anyone will miss the point," Mrs. Reagan says next. "The thrill can kill. The drug dealers need to know that we want them out of our schools, neighborhoods and our lives. And the only way to do that is to take the customers away from the product. Say no to drugs and say yes to life."

The Eastwood-Reagan spot is a variation of other 40- to 90-second messages by:

Rosanna Arquette -- "Do you think risking your life for a 10-minute high is worth it? I don't."

James Woods -- "Every time you do it, every single time, you risk ending up on a slab in the morgue. Doing drugs can be stupid enough. Doing this drug can be terminally stupid."

Rae Dawn Chong -- "Once you start smoking it you gotta have more and more because the highs get shorter and the lows get lower. And when you run out of money to buy it you'll lie, you'll steal, you'll do whatever it takes to get more."

Dudley Moore -- "Crack can kill you. For a 10-minute high. Not too funny."

Pee-wee Herman -- "Look, everybody wants to be cool but doing it with crack isn't just wrong. It could be dead wrong."

Bette Midler -- "If anyone offers you some, tell 'em where to shove it."

Roy Scheider -- "Sure, your friendly neighborhood drug dealer can guarantee to get you great crack, but what you got to remember is he can't guarantee it won't kill you."

Olivia Newton-John -- "For every time you try it it's a guessing game. If you guess wrong with this stuff, you die."

In addition to reporters the premiere audience included several congressmen from the House Select Committee on Narcotics Abuse and Control, including Democrat Charles Rangel, committee chairman, and ranking Republican Benjamin A. Gilman.

Valenti said MPAA's members spent about $160,000 on the trailers, which, if talent hadn't been donated, would otherwise have cost $500,000. More trailers will be added in time, he said.

"As soon as drugs end we'll end the campaign," said Weintraub.

As for how the Reagan-Eastwood pairing came about, Weintraub said, "That's easy. Who else would you cast opposite Clint Eastwood?"

He went on to say that Mrs. Reagan had been asked who she wanted as her costar, and she chose Eastwood.

Explained Weintraub: "Her husband wasn't available."