Let’s say you’re a serious actress, steeped in theater training. What do you do for a living?

Well, Gillian Anderson spends some time seeing and not seeing UFO’s. She and her “X-Files” partner pretended to see them together for one episode in the wee hours of the morning. “It was, like, 2 o’clock in the morning and we were standing on this hill and it was kind of drizzling,” Anderson groans.

“And we both had to synchronize our eyes with the way the UFO’s would eventually be moving . . . We stood there for God knows how long.”

OK, let’s say you’re a serious actor with an Ivy League education. What do you do for a living?

Well, David Duchovny spent some time lying on a parking lot, pretending to be horrified.

“We did an (‘X-Files’) episode with kind of a beast-woman,” Duchovny says, “a feral humanoid . . . She was 6-foot-1 and matted hair, and beautiful in her own way.”

The director decided his reaction wasn’t horrified enough. It had to be reshot.

“The X-Files” is not your standard TV show.

The series, at 8 p.m. Fridays on Channel 32, is the home of UFO’s and the paranormal. It’s the place for beast-women, arctic monsters and more.

This week, it has a killer who can switch gender at will. You don’t see that very often, even in rock ‘n’ roll.

And one more thing: In its own way, “The X-Files” is a terrific show.

” ‘The X-Files’ is a show people are really starting to talk about,” says Fox programming chief Sandy Grushow.

Lucy Salhany, his boss, goes a step further:

‘ “The X-Files’ is a hit,” she says.

Fox officials are prone to exaggerate, of course. This time, however, there’s a kernel of truth.

In an awful time slot, “The X-Files” has found viewers. This year, Grushow says, it’s given Fox a 27 percent increase for the hour.

When people discover the show, they find a terrific blend.

The filming (in Vancouver) is stylish and the music (by Mark Snow) is terrific. Duchovny and Anderson create believable characters, from surprisingly solid scripts.

At the core is a fascination with the unexplained and the unexplored.

The groundwork was laid during previous seasons, when the “Sightings” documentary series held the time slot. Indeed, producer Henry Winkler implies that the show was canceled mainly because of company politics.

” ‘Sightings’ was produced by an outside company,” Winkler says, “and ‘The X-Files’ is done by . . . Fox itself. I have never watched ‘The X-Files,’ and may they live in health.”

Whatever the reason for the change, “The X-Files” started with a core of believers. Then it added a layer of dramatic oomph.

Anderson, who plays the show’s skeptic, is sometimes a believer in real life. “I have, for a long time, believed in certain aspects of the unknown — ESP, psychokinesis, UFO’s.”

Duchovny, who plays the believer, leans the other way.

“I believe in the abstract, but not in the specific,” he says. “If you ask me if I believe in the possibility of the things we do on the show, I would say yes. But if you ask me if I believe that they actually have happened, I’d say no.”

And producer Chris Carter thought that he was a pretty good buff of these things . . . until he met his staff.

Two of them brought their own extensive library, Carter says.

“But they had these crazy journals and newsletters that come from who-knows-where,” he says. “And they were able to write a story using a lot of very factual, if you will, information.”

Now “The X-Files” has become part of the lore. One intense letter was mailed to Fox Mulder, Duchovny’s fictional character; zealots already have started storing “X-Files” trivia.

These are the newest variation of Trekkers or Leapers, but without an official name. “I’m calling them ‘File-o-philes,’ ” Carter says.

That’s not so bad, actually. On a Friday that includes Urkel and old detectives, we could do worse than become a nation of File-o-philes.