Only yesterday we were contemplating the TV movies certain to be made about the trial of Jean Harris for murdering diet doctor Herman Tarnower. Sooner or later there would be at least one.

It turns out to be much, much sooner -- tonight and tomorrow night at 9 on Channel 4 in fact, when NBCpresents its two-part "People vs. Jean Harris," the trial thus going from real life to TV life in probably record time. The executive producer of the special, former NBC executive Paul L. Klein, thinks he has invented nothing less than a new form.

"We're running an ad calling it, 'The Drama of Reality,'" says Klein from a record rented Malibu beach house."Some people are calling it a 'docuvent.' I don't know what you call it. I'd call it 'Real Drama,' but since 'Real People' [the NBC show] is not real people but freaks, that's going to lose credibility."

Whatever it is, it was done in a flash. Harris was sentenced to 15 years in prison for the murder of her lover on March 20; only a week earlier, Klein got the go-ahead from NBC and an air date for his show. At that point, there was no script, no director, and one had been cast. Later Ellen Burstyn was signed to play Harris and Martin Balsam her defense attorney, Joel Aurnou.

What they enact is only the trial itself, not the murder nor any events outside the courtroom. How fascinated one is by the result -- judging from a rough cut of the tape submitted for preview -- probably depends on one's interest in the trial in the first place. As television it is dry and slow-moving, but Burstyn's performance as Harris is an unfailingly attentive and detailed one.

It has the effect of making Harris an extremely sympathetic figure, talking about her plans to commit suicide ("I intended to kill [pause ] myself") and her low self-esteem ("I was a person no one ever knew" is read from a note she had written befroe the shooting).

Ironically or not, then, Harris through attorney Aurnou yesterday issued a statement saying she has "strenuous objection" to the program and "vigorously opposses" it. Aurnou claimed it is an infringement of her civil rights since there is an appeal of her conviction still pending. It could be that property rights rather than civil rights are more at issue here. Late last week, wire services reported that Harris had asked for permission to watch the dramatization on TV in prison.

Does Klein have the legal right to portray the trial participants on TV, without getting their permission? "We're insured," he responds.

"This is the public record," says Klein. "In the trial, when the prosecution wanted to read the Scarsdale letter [a hostile bombshell fired off by Harris to Tarnower], her attorney says, 'Well, if you want to read it in a public courtroom for the public record, okay.' That's the nut of the whole idea: the public record. The privacy of the courtroom is controlled only by the size of it. Print people go in there and then come out and tell everybody what happened. That's what we're doing. We're reporting it to the rest of the world."

Naturally another crossbreed of reality and fiction is bound to bring cries of alarm from the usual quarters. Klein, nothing if not a practical man, says his writer, George Lefferts, was "under rigid control," and that "every word has to be exactly the way the person said it" at the trial. Lefferts's main job was editing; he cut a 10,000-page trial transcript down to 300 pages for the three-hour show.

Director George Schaefer kept things very judicial -- it not entirely judicious in terms of holding a viewer's attention. After an hour or so of this measured and largely unmodulated re-creation, you begin to long for the hokey melodrama of the traditional movie of TV courtroom scene -- some hysterics, or theatrics. Burstyn's convincing sniffles and tears are about as lively as it gets.

Klein, perhaps the only deep thinker ever to program a network, says all he had to do to get hold of the transcript was buy it for $1.25 a page from the court reporter, although when a trial runs to 10,000 pages, that gets a little expensive.Aurnou claimed yesterday that the transcript is still incomplete and that Klein's version is ipso facto a distortion.

Klein has also "brought" the Carol Burnett-National Enquirer libel trial and the transcript of testimony given the Nevada gaming commission when Frank Sinatra was making his bid to become part-owner of a casino. Whether those trials will see the light of television remains to be seen.

Regardless, Klein thinks more and more TV will be of this quick, instant sort. Why should people spend months on a movie that may be forgotten the morning after it is shown? Television always has specialized in disposable entertainment. And with production costs skyrocketing, and there being no foreseable shortage of exploitable news stories, Klein's Polaroid-playhouse approach may become very popular.

"We did the whole thing in less than eight weeks," says Klein. "Normally to produce a three-hour show takes 14 months, minimum." Klein compares his new fast-food form of programming to Japanese cars -- smaller and more economical. And the wave of the future.

"A Honda runs better than a Cadillac," Paul Klein says.

The production schedule for the taped play was almost as dramatic as the trial. The tape was to have been finished yesterday, the day before air time, and put on the last flight from Los Angeles to New York last night from arrival in New York this morning.

Klein says he got the idea to dramatize the trial from a network newsman he won't name; the man said to him, "You know what'll make a great soap opera? The Jean Harris trial." Originally Klein wanted it to be a daytime serial of 20 weeks' and 100 episodes' duration.But the network wanted it for prime time.

NBC President Fred Silverman, Klein's former boss, doesn't like the idea, Klein says, but top executive Irwin Segelstein did, and shepherded it onto the air. Silverman and Klein are not pals, and Klein's assessment of Silverman's record at NBC is, "For three years, he's been wrong virtually every time."

Klein is one of America's great complainers. He gripes of the early air date that Silverman gave him, "While I'm disappointed at the date, and there's no reason for it, I just wanted to prove that we could do it." Television is not the business it used to be, he says. "There are only seven, eight people in the world who know anything about commercial television. sThere's no real programming going on and only a few people who know what the business is."

Why does he stay in television if he hates it so much? "No, I really like it! I'm unhappy not running a network. I know more than most people." Would he ever be willing to go back to NBC, where he returned in 1976 as head of programming after a lengthy absence?"I don't think there'll be an NBC," says Klein.

"No one's ever gonna hire me," he says. "I'm too outspoken."