Katie Featherston and Micah Sloat play the young couple haunted by a spectral force in the breakout hit “Paranormal Activity.”

Hollywood ? Just a few weeks ago, Katie Featherston was balancing plates brimming with spaghetti and baked ravioli, working as a waitress at a local Buca di Beppo restaurant. Micah Sloat was a struggling actor/computer programmer living in North Hollywood. Now, they’re watching the micro-budget horror movie they filmed three years ago develop into a full-blown phenomenon.

The two play the young couple haunted by a spectral force in the breakout hit “Paranormal Activity.” The suspenseful supernatural thriller, reminiscent of “The Blair Witch Project,” has become one of the year’s biggest success stories. Made for $15,000, “Paranormal” was the No. 1 movie at the box office this weekend, taking in about $22 million, and has earned an astounding $62.5 million since its initial limited release in late September.

Featherston and Sloat? They’re just as surprised as everyone else.

“When the movie opened, we hid behind a tree across the street from the ArcLight (theater) in Hollywood,” Featherston, 27, said as she sat in a booth at Buca di Beppo, where she was frequently interrupted by former co-workers. “The line was huge. I couldn’t believe it. It’s something you hope for but never, ever expect will happen. I wanted to run over and say, ‘Hey, I’m in that!’ … but we couldn’t.”

In an attempt to keep the mystery surrounding the movie’s story intact, the studio and the film’s director, Oren Peli, an Israeli-born video game designer with no formal film training, kept the two actors relatively secluded — they’ve only recently started to do interviews with media.

Real people

The tactic seems to have worked. After the movie’s nationwide release, the startling ending to the film provoked a spike in Internet searches by people apparently determined to learn if the facts as presented were true.

It’s all been a big leap for Sloat. The 28-year-old, who grew up in Westport, Conn., and moved to Los Angeles in 2005 to pursue acting, was on the verge of ditching the unstable career and giving up on his dream.

Featherston, a Texas native, graduated from Southern Methodist University and also moved to Los Angeles in 2005.

When the two auditioned for the spookfest in 2006, they weren’t expecting to be part of a box-office record breaker. There wasn’t even a script.

“I remember being in the waiting room and these girls would just kind of walk out shaking their head,” Featherston said. “I walked into the room and (Peli) said, ‘Why do you think your house is haunted?’ Just like that. Boom! So I just threw myself into the character.”

And that’s exactly what Peli was searching for in casting the characters who would later be called Katie and Micah (yes, he used their actual names).

“The whole point is for it to feel natural,” Peli said in a recent phone interview. “I didn’t want actors who looked like they were acting. I wanted it to feel real, so I didn’t want there to be a script. I wanted the audience to think they were watching real life. If you’re looking at the footage of their audition and see the way they interact — if you didn’t know any better — you’d think you were looking at real documentary footage of a couple.”

It’s true. In person, they often finish each other’s sentences. They playfully tease one another. Compliments are exchanged. But despite the good-natured flirtations, they insist they’re not a couple, although Sloat is quick to point out that Featherston asked him for his number back when they auditioned together.

“I was not trying to hit on him,” Featherston interjected. “I was new in town and we had so much fun together. Why wouldn’t I want us to be friends and hang out? And I thought if we got the part, it would be nice if we got along because it was going to be intense.”

Universal fears

Filming took place in 2006 at Peli’s San Diego home over a span of seven days — a problem for Sloat, who was enrolled in music school at the time (he even wrote original music that’s included in the film).

The actors, who were each paid $500 for their roles, often put in 14- to 18-hour days. The little sleep they managed to squeeze in took place in the “haunted” house.

Featherston slept in the infamous bed seen in all the promotional screen shots of the film, while Sloat dozed off in one of the guest rooms.

“We hardly saw the outside world,” Featherston joked. “We just filmed all the time. I couldn’t even tell you what San Diego is like. But the exhaustion helped make our characters more believable — I think.”

Believable acting aside, Sloat said, it’s the universal primal fear that makes this thriller so spine-tingling.

“Being scared at night is something we can all relate to,” Sloat said. “As children, we all had those fears. Everyone knows what it’s like to be scared of what’s lurking behind the closet. I think as we age, those kind of unconscious fears recede into the background, but they’re still there. And when they reappear in your home — in your room — it’s not something that you can just ignore. I think that’s why it’s done so well.”

Sloat and Featherston — who look much like they did three years ago (although on this day Featherston is a bit more glam with the help of an on-site makeup artist) — don’t seem fazed by the frenzy. They don’t mind it either.

Featherston quit waitressing. Sloat hinted he’s leaving the tech industry. “Auditions are coming at us like bullets,” Sloat said. “It’s better than winning all the lotteries at once.”