Billy Crystal was watching a television show about ''fantasy vacations'' when he had what he called an epiphany. ''You ever had an epiphany?,'' he asked. ''I have them all the time.''
Epiphany has several meanings. One is ''the sudden, almost divine understanding of a particular subject.'' That was the kind Crystal had.
''I literally wrote down 'City Slickers' as I watched the show,'' he said. ''I put it down as the title of my next film, and I went so far as to write Jack Palance's name down. I wanted him to be in the cast. I figured I would do a film about three city slickers who go to a dude ranch for a 'vacation' and run into a trail boss, played by Palance, who would teach me about life. Like Yoda. Life from a cowboy's view.
''That was 18 months ago," he said. "Here we are with 'City Slickers.' "
In the film, which opens here tomorrow, Crystal, Daniel Stern and Bruno Kirby are New Jersey residents who visit a dude ranch where they will herd cattle for the fun of it. It will be their vacation.
''The jokes were the easy part of it,'' said Crystal. ''We also wanted to do a movie about friendship, about fathers and sons, about becoming a parent. It was all there when I went to the writers.''
The writers were Lowell Ganz and Babaloo Mandel, who have done, among other scripts, ''Parenthood'' and ''Splash.''
''I had never met them, but I had an instinct,'' said Crystal, who served as executive producer for ''City Slickers.'' ''We brought out the best in each other.
''I knew what we had,'' he added. ''We had a small story which would be told against a large landscape. It's amazing. The very first movie I ever saw was 'Shane,' and here I am doing a film with Palance.''
Crystal doesn't think of the new film as a western. ''It has the essence of a western," he said, "but I don't know that it is one.''
Being both the star and the executive producer of the film didn't bother him. ''It all felt very comfortable,'' he said. ''There was more pressure, of course. There was pressure to do the film under budget, but it was pressure in a good way. It was my first chance to get my comedy and my sensibilities into a film.
''It was like having a suit of clothes made from scratch," Crystal explained. "We talked all of it over. I was totally involved with Marc Shaiman, who did the score, and it all felt very natural. I'm being very creative lately, and I'm enjoying what I'm doing.''
Some people will say that Crystal's new movie is a change, but he likes that. ''I want to change,'' he said. ''The worst thing is to hear people say I haven't changed. This is a film that makes you appreciate the outdoors and animals.''
The movie is also about men meeting their mid-life crises, and Crystal says he has had one of his own. ''It happened as I approached 40,'' he said. ''Actually, I never become 40. I tried it, didn't like it and went back to 36.''
Today, he is 43, and his mid-life crisis occurred when he sent his daughter off to college. ''The whole family was splintered at the time,'' he said. ''My daughter went away, I was off working, and my wife stayed at home, so I know what a mid-life crisis is.''
He's become partial to cattle. In the film, he befriends a calf, one that becomes his pet. ''I can't eat veal anymore,'' he said. ''I haven't eaten it in a year. I just can't.''
He was given the horse he rode in the film. He didn't really want it, but he felt he couldn't refuse it, so now, it is housed 1,000 feet from his home. ''I didn't want it to be a summer romance,'' he said. ''I don't see him much, but I know he's there.''
He takes part in a stampede in the film. That is, he sits in a tree as the cattle rumble past him. He doesn't know if he would do that again. ''You can see it all in the movie,'' he said. ''I'm sitting in a burned-out Joshua tree. One steer came so close, that if his horn had been a little longer, I'd have been comic tartare.''
The advance reaction to ''City Slickers'' has been positive, but Crystal is cautious. ''It's been almost too good,'' he said. ''I would rather be quiet about it and let people like it.''
If he hadn't been a performer, what would he have liked to do?
''I'd like to learn to be a painter,'' he said. ''Like Picasso. I'd like to play him, too.''
So what's next?
''I'm planning to do a movie called 'Junket,' '' he said. ''I'm serious about that.''
Told that someone had written a book on a television junket some 30 years ago, he seemed interested. ''I'd like to read it,'' he said. ''I'm also planning to direct a film called 'Mr. Sleep.' It's 40 years in the life of a comic. It will be hard-edged.''