Most odd-couple buddy pics are born in the thrumming noggins of Hollywood agents trying to pair disparate clients, or are the thunderous brainstorms of studio execs mixing and matching talent to work box-office magic.

The idea of teaming John Turturro and Woody Allen - as in the soft-touch sex-and-religion comedy Fading Gigolo - came from a different source: their barber.

"It is true that the guy who cuts my hair also cuts Woody's," says Turturro, who not only stars in Fading Gigolo, but also wrote it and directs. "We would always talk, and he would say, 'You know, you should work with Woody.'

"And then one day the idea sank in, and I thought, well, it would be interesting. . . . There could be good chemistry, because we have certain things in common, and certain things that are very different - different ages and sizes.

"And I don't know if I asked the guy who cuts my hair, or told him, but, somehow, Woody heard the idea and liked it and asked me to come in."

So the collaboration - Turturro writing and rewriting, Allen offering feedback - began. Practically before anybody knew it, they were filming.

In Fading Gigolo, opening Friday at select area theaters, Turturro is Fioravante, a guy who worked in an indie bookshop run by Allen's Murray - a bookshop forced by the nature of publishing and New York real estate to close.

To cushion the economic blow, Murray has the out-of-the-blue notion to put Fioravante to work servicing women for a fee. He could start with Murray's lonely dermatologist, played by Sharon Stone, and go from there. "From there" includes Sofia Vergara as Stone's adventurous friend, and Vanessa Paradis as a widow in Brooklyn's orthodox Hasidic community.

"It's just a cavalier idea - and sometimes that happens in life," Turturro says. "Just like the idea of me working with Woody. Then, when we acted together, I could see that we had this ease between us."

Fanciful though the concept may be of Allen playing a pimp to Turturro's not-exactly-Jon Hamm-ish male escort, the writer and director knew he had to ground his story in the real. Research was done.

"I talked to some men and some women, read books, watched documentaries," Turturro says. "I wasn't interested in the sordid, exploitive side of things. I thought, 'Listen, this movie can only cover so much territory.' But I wanted to find people who felt that they had made some kind of contribution in the exchange that they had with their clients - and I did.

"People felt like, 'Hey, I do definitely help release tension, or educate someone, or help them through a grieving process.' It's not always the same coked-out story that we see. . . . These cliches that we're inundated with - you're surprised when you meet someone and they tell you, 'No, no, I make people happy. And I'm happy.' "

Turturro cites Fellini's 1957 classic Nights of Cabiria, starring Giulietta Masina, as a movie about a prostitute that avoids the stereotypes ("her spirit is irrepressible"). He also says he knew, early in the writing, that he needed to address the way women are treated in certain religions and cultures. Hence, Paradis' Avigal, untouched by a man since her husband, a rabbi, died many years before. Liev Schreiber, as a neighbor who has known Avigal since they were teens, doesn't like the look of things when he sees her going off to Manhattan and sees Turturro's character coming to her.

"The women in many religions have to live with rules made by men," he says, "and you can have a kind of empathy for their plight in life, and their position . . . . The difficulty of being a woman in life."

About Paradis, the French actress who recently split from longtime beau Johnny Depp, Turturro had this to say:

"She changed the DNA of the film. I always hoped that it would be moving and delicate, but she just brought something so special to it, and when I saw her with Woody early on, I felt, wow, this is interesting, this is going to affect the whole movie. Woody was completely convinced she was like a Hasidic Jewish woman."

One of the, um, climactic events in Fading Gigolo is a proposed menage among Fioravante and the close friends played by Stone and Vergara. It's no real spoiler to say this threesome does, indeed, occur, and Turturro - wearing his director's cap and his actor's cap (and not much else) - had to figure out how to do it.

"Those scenes, sex scenes, are always difficult, whether you're the director or not," he reports. "The original way the scene was designed, I thought it looked too pornographic . . . . So I tried to do it in a way that would leave the most to the imagination and yet could still play. But it was crazy.

"I actually thought at one moment, 'You know what? It's one thing to write this, it's another thing to actually do it.' Because everyone's trying to look good - and it's so far away from the actual thing that you would be doing."

But Turturro is a professional, playing a professional.

"You go back, you take care of everybody, and keep them relaxed," he says of the scene, which took the better part of a day to stage and shoot.

"It takes a long time to get the ladies ready. And myself."