The Mod Couple : At a video shoot for Trent Reznor’s remix of a David Bowie song, their mutual admiration society is displayed.

“Hey, that guy kinda looks like David Bowie. . . . Naahh, can’t be.”

The speaker is part of a growing crowd of onlookers on a downtown Manhattan street. Surrounding him are police officers, paparazzi, men and women carrying walkie-talkies, tourists with cameras and other gawkers--all clear signs of a celebrity in the neighborhood.

Still, the doubting passerby has reason to be skeptical. Why would a rock star of Bowie’s stature be racing frantically down the street on an unseasonably warm afternoon, dressed in a wool turtleneck sweater and a paisley suit? And why would he be chased by a disheveled young man who kinda looks like Trent Reznor, the driving creative force behind the intensely disquieting rock band Nine Inch Nails?

The short answer is that Bowie, 50, and Reznor, 32, are shooting a video together.

Earlier this year, Reznor expressed interest in remixing the song “I’m Afraid of Americans,” a wry slice of electro-funk from Bowie’s most recent album, “Earthling.”

The project quickly blossomed into an EP, which arrived in stores on Tuesday, featuring six new versions of the Bowie track--five by Nine Inch Nails and one by British techno savant Photek. The EP’s first mix, on which Reznor sings backup, will be heard in the video.

Why the collaboration?

“We’re the two most intelligent people we know,” Bowie quips. “Who else could I give my mixes to? And who else would he work with?”

Indeed, although many younger artists have cited Bowie as a major influence, Reznor’s particular blend of artistic and electronic ingenuity and his thoughtful, sometimes dark irreverence seem to have engendered a special bond with his continually adventurous, forward-thinking idol. The two first worked together in 1995, when Reznor invited Bowie on a North American tour with Nine Inch Nails that brought together two of the most exciting forces from two different rock generations.

Cooling down in Bowie’s trailer during a break in filming the video, which casts Reznor as a mad taxi driver and Bowie as a paranoid Englishman whom he follows around the city, the two musicians are at first blush a study in contrasts. The older icon, looking impossibly crisp and cool in his heavy attire, is witty and gregarious; Reznor, dressed down in an equally stifling trench coat, is soft-spoken and appears quite shy.

But when the two discuss working together, there emerges a level of empathy and mutual respect that clearly transcends such superficial differences.

“Trent and I were drawn to each other’s work before we ever met,” Bowie stresses. “And I think, if I can speak for both of us, that [the EP] is a tentative step towards a much more unified working relationship. What that will be, I’m not really quite sure. We’ll stay autonomous artists, of course; but I think that in working together on some effort, we could do something earth-shattering--probably something like neither of us has done before.”

Adds Reznor: “I just started working on my own new album as I finished these remixes; and it made me think, ‘OK, I still have my [expletive] together.’ It made me proud.”

Bowie beams. “Trent’s such a perfectionist. . . . There’s a lot of myself, when I was his age, in him.”

In addition to harboring affection and admiration for each other, both men offer high praise for the pair of hot young British directors who are working with them on this video. Dom and Nick, as the 26-year-old upstarts call themselves, have already directed popular videos for Oasis (“D’You Know What I Mean?”) and the Chemical Brothers (“Setting Sun,” “Block-Rocking Beat”). And their approach to dealing with rock stars is apparently quite hands-on. On the set, they literally get in Bowie’s and Reznor’s faces, by turns instructing, cheering on and joking with the musicians.

“They’re a new school,” Bowie muses. “A lot of [video directors] see everything they do as potentially a show reel for Hollywood producers. These kids really love making videos . . . and they’re very good at getting that very British, gritty, shot-on-a-shoestring quality. They work exactly like filmmakers, doing only one or two takes, so everything looks real-time.”

Says Nick: “David had a lot of input into what we were doing. He really liked the concept of being an alien abroad. . . . And Trent’s brilliant. He even started improvising. He’s a bit of a Method actor, Trent. He got into his part so much that at one point he managed to smash the windshield of the taxi with his hand. I don’t know if that’ll make it into the video, but it was pretty exciting stuff.”

While Bowie and Reznor have each been noted for their innovative videos, and while they’re clearly enthused about this joint effort--”It’s better than any [video] I’ve ever done with my band,” Reznor says--neither is entirely uncritical of the medium.

“A kind of soul-destroying thing I’ve dealt with is that . . . you have to hire someone else to represent your song in a visual aspect,” Reznor says. “And then, even if you have a great director, it’s like . . . do I spend this much money to cater to a very rigid MTV market and censorship arena?”

“Also,” Bowie says, “all currency is devalued by too much familiarity. I’m sure there are videos being made monthly that would have blown people away 15 or 20 years ago, but now they don’t have as much impact. You’ve got to come up with cinematic ideas that are potent and original . . . but it’s hard to experiment too radically. There’s a tight format of what you can and can’t do.”

Bowie and Reznor agree that videos are still important marketing tools, despite recent reports of MTV’s decline in popularity among young adult viewers. But Bowie modestly insists that Reznor is more vulnerable in this area “because he’s so [expletive] popular! . . . I suspect he’ll continue to be one of the more important American music-makers.”

Before Reznor can return the compliment, Bowie pipes up, “I know I’m good, too--don’t worry! But Trent’s got it. He’s for real.”