For Top-Secret Narration, Call Charlton Heston : Security: For six years, the actor has held the nation's highest Q clearance to enable him to narrate classified films and videotapes.

The department said Reagan simply retained the clearance status he gained as President. Heston's Q clearance, originally issued in February, 1983, is up for routine, periodic renewal, an Energy Department spokesman said. A Q rating is equivalent to the highest levels of top-secret clearance in the military.

Former President and actor Ronald Reagan also holds an active Energy Department Q clearance, as the advanced classification is officially called. Q clearances are held by more than 28,000 Energy Department, Nuclear Regulatory Commission and defense-contractor employees involved in nuclear weapons programs, according to the department.

In a rare glimpse inside the defense Establishment's relationship with Hollywood, the U.S. Department of Energy has acknowledged that actor Charlton Heston has for six years held the nation's highest-level nuclear weapons security clearance to enable him to narrate classified films and videotapes.

Neither Reagan nor Heston can simply walk into the Los Alamos National Laboratory in New Mexico and ask, for instance, to read through the assembly manual for hydrogen-bomb triggers. The Energy Department said that cleared individuals must show a need for specific information before they may gain access. Seeing the Heston films also entails a need-to-know--people with Q clearances themselves.

The Energy Department's Q clearance is apparently not Heston's only security classification. Heston said that he has done classified work for other agencies, but declined to identify them or the projects involved. The Defense Department and the Central Intelligence Agency declined to respond to inquiries about clearances that either agency may have separately arranged for Heston.

Charles Barnett, head of video and film production at Los Alamos and a longtime acquaintance of Heston's, said the classified relationship began by chance when he was discussing a film project with a Los Alamos scientist who assailed the poor quality of narration on a previous production.

"He said, 'I hope you're not going to give me that same awful narrator,' " Barnett recalled. "And I said, 'Who in the hell do you want, Charlton Heston ?' And he said, 'Could you?' "

It seemed ridiculous at first, Barnett said, but then he got to thinking. Even though the audiences for most of the classified films are internal--restricted to scientists, defense officials and others--Barnett said he felt production quality was still important.

Instead of simply dismissing the conversation, Barnett said he called Heston just to see what the actor would say. To his surprise, Barnett said, Heston agreed to the project. Barnett said Heston has never accepted a fee for his top-secret appearances.

And as to whether it was appropriate to involve a Hollywood star in top-secret nuclear weapons programs, Barnett said he had a simple line of reasoning: "If you could get Charlton Heston to narrate your films for nothing, wouldn't you?"

Barnett said Heston is the only superstar in his classified talent stable. Other narrators employed by Los Alamos, Barnett said, include local broadcasters and one person who has narrated sequences on public television's "Nova."

"I'm not trying to be dramatically secretive or anything," said Heston, who has also served as a public spokesman for the National Rifle Assn. "But I can't get into that (his other classified activities). I do work for other agencies from time to time. Most of the stuff that you do in this area is not designed for public consumption."

The practice of involving Hollywood figures in defense film projects dates at least to World War II, according to Howard Suber, co-chairman of the film producing program at UCLA. Much of the interest in Hollywood personalities, he added, has stemmed from their ability to attract the attention of viewers of training films and other government productions. "The problem the government always has with these films," Suber said, "is that they are incredibly boring."