When they began writing “The Oranges,” Ian Helfer and Jay Reiss had been friends for 15 years but had never worked together. The timing was right: “We knew each other so well by then, we were willing to go to war and knowing that was OK,” Helfer explains. “I think teams that have a strictly professional relationship have to be a little more polite.”

Lack of politesse apparently worked, because “Oranges” — about a young New Jersey woman who has an affair with her parents’ best friend — not only was a favorite among Hollywood execs, it has a start date (April 6).

The scribes, both transplants from New York, also have had their separate careers. Helfer has been a sometime actor and writer for the comedy group Stella and old college roommate/helmer John Hamburg. Reiss sold his screenplay “Lonny the Great” to Warners and is writing the feature adaptation of Chris Waitt’s docu “A Complete History of My Sexual Failures.”

But there is strength in numbers, even if that number is two.

“It’s an amorphous thing why it works,” Reiss says. “Sometimes I would do a draft, sometimes he would. I hear of teams writing every line of dialogue together, one person over the other’s shoulder, but this wasn’t that. We were facing each other, blipping the information back and forth, discussing it, trying to work it out. While it took longer than writing something myself, you end up with more of a finished product, even by the end of the first draft.”

“One of the big surprises is that it’s become such a well-liked script,” Helfer adds, “because toward the end we started to refer to it as ‘The Repugnants.’ Jay was so sure nobody would like it. Luckily, he was wrong.”

AGES: Helfer, 38; Reiss, 41

HOMETOWNS: Helfer: Manhattan; Reiss: Plainview, Long Island

INSPIRED BY: Hal Ashby (Helfer); Tom Stoppard (Reiss)

UP NEXT: Helfer: a new John Hamburg pic, “Bob, Again.” Reiss: “The Complete History of My Sexual Failures” for Neal Moritz and Jay Roach at Universal.

REPS: Helfer, agents: Sandra Lucchesi, Eric Garfinkel (Gersh); manager: Danny Sherman (Principal); attorneys: Michael Schenkman, Greg Slewett (Bloom Hergott). Reiss, agents: George Lane, Gregory McKnight (CAA); managers: Ilan Breil, Paul Nelson (Mosaic); attorneys: Adam Kaller, Ken Richman (Hansen, Jacobson, Teller, Hoberman, Newman, Warren & Richman)