In Friday's episode of "Medium," Allison (Patricia Arquette) finds herself inside the horror film "Night of the Living Dead."

The original 1968 version, that is. Not the 1990 remake.

The idea for the episode dates back to "Moonlighting," believe it or not. And that is not a joke about Cybill Shepherd.

"It's actually the vestige of an idea that I had way back when I was doing 'Moonlighting,'" said "Medium" creator/executive producer Glenn Gordon Caron, who was also the creator/executive producer of the 1985-89 Shepherd-Bruce Willis series.

Back when "Moonlighting" was still in production, Caron had bought the rights to the 1964 movie "Mothra vs. Godzilla."

"We were going to matte Bruce and Cybill into it," Caron said. "And it was one of those ideas I just never got around to doing."

(He didn't tell us which one of them would have played Godzilla. My money is on Shepherd, however.)

But the idea of using an old horror film for a new TV episode had always been in the back of Caron's mind.

"So this year we've actually gotten the rights to the original 'Night of the Living Dead.' And we're going to insert Patricia into it," Caron said.

And, within the context of the show, it actually makes sense. Remember, the premise of the show is that Allison sees dead people in her dreams.

Zombies are dead, after all. So seeing the zombies in "Night of the Living Dead" makes crazy sense.

"I was so excited about it because I love that movie," Arquette said.

Well, I suppose I should also tell you that Allison's vivid nightmares leave her with cuts and bite marks. And it's all somehow related to the murder of a funeral director.

If you guessed that this day-before-Halloween episode is not coincidental, you'd be right.

For Arquette, the episode is sort of blast from her past in a couple of ways. For one thing, she was a fan of horror films when she was growing up.

"When I was a teenager, it was kind of like when you start breaking away from the establishment and your parents," she said. "It's like you find these jewels (on TV) after school, really at a weird time, in the hot California sun, watching this weird movie. So it's really exciting to be in it.

"Also, I started out in horror films."

Her first screen credit was in the 1987 movie "A Nightmare on Elm Street 3: Dream Warriors."

Weirdly enough, the character she played in "Nightmare" — 16-year-old Kristen Parker — had something in common with her "Medium" character, Allison. When she was a child, Kristen had the ability to pull her father into her dreams.

And, of course, the villain in the "Nightmare on Elm Street" movies, Freddy Krueger, killed teenagers in their dreams.

"So I love a good monster movie," Arquette said. "Here I am in a monster show.

"I'm not the monster, but it's exciting."

e-mail: pierce@desnews.com