Though Natalie Portman and Ashton Kutcher may have been the first to harvest the seeds of non-committal sex in “No Strings Attached,” Justin Timberlake and Mila Kunis can rest assured that they avoided any sloppy seconds with their film, “Friends With Benefits.”

As directed by Will Gluck, who helmed last year’s head-turning surprise hit “Easy A,” Timberlake and Kunis star as Dylan and Jamie, a pair of recently acquainted singles who decide to dive into a sexual relationship devoid of labels or commitment. For a while, their needs are sated, until, soon enough, real emotion begins to boil to the surface.

What sounds like a pat and hackneyed scenario is really anything but. “Friends With Benefits” is a consistently funny, surprisingly un-clichéd story told with warmth and admiration for its characters. Timberlake and Kunis, who share a great deal of comedic and romantic chemistry, are given a surplus of clever dialogue to accompany a story that feels as modern as it does traditional.

Like many of his peers, Gluck litters his film with a bevy of references, both filmically and otherwise. At their strongest, these references work in placing “Friends With Benefits” both culturally (with its depictions of iPads and flash mobs) as well as cinematically. For instance, on the evening of Dylan and Jamie’s first sexual encounter, the two hook up under the watchful eyes of Clark Gable and Claudette Colbert, giving “It Happened One Night” a salacious double meaning.

In another scene, Jamie and her mother (Patricia Clarkson) discuss the concept of free love as the film “Bob & Carol & Ted & Alice” (a post-code sex comedy about a pair of spouse-swapping couples) plays surreptitiously in the background.

These touches are Gluck’s deliberate way of presenting “Friends With Benefits” as a romantic comedy with an appreciation for history but an affinity for the present. He and screenwriters Keith Merryman and David A. Newman borrow generously from classic American cinema, particularly the genre of screwball comedy.

Critic Andrew Sarris describes the screwball comedy, which was most prominent in the ‘30s and ‘40s, as “a sex comedy without the sex.” It featured characters who, rather than fall in love in the traditional sense, instead come together through a series of farcical situations. Often, the romantic leads in a screwball comedy begin as adversaries (with the woman acting as the main aggressor) before eventually falling in love, with the end result being either a marriage or at least the promise of marriage.

In the case of “Friends With Benefits,” Dylan and Jamie are never adversaries. And they have plenty of sex. What makes the film screwball-esque is the distinct lack of romance between them. At least initially, they really are just in it for the physical pleasure. Of course, that all changes—but because of the way Gluck structures his film, the change comes over a period of time in which a number of zany scenarios are thrown into the mix, creating obstacles and conflicts.

Where Cary Grant and Katherine Hepburn had a renegade leopard on their hands in “Bringing Up Baby,” Dylan and Jamie wrestle with their burgeoning feelings for one another—something both characters share a distinct aversion to.

This aversion is key: In the case of “Bringing Up Baby,” it’s Grant rejecting Hepburn’s advances, refusing to acknowledge any kind of romantic inclinations; in “Friends With Benefits,” the main characters actively deny their own emotional needs. This 21st century examination of self-sabotage renders the film as something of a neo-screwball, where male and female characters alike seem to revel in their own misguided self-importance before opening themselves up to love and to being loved.

What results is something of a cathartic experience. “Friends With Benefits” isn’t the most rewarding film of the year, but it might just be the most refreshing. More than a mere genre riff, Gluck’s film is a reclassification of a classic cinematic trope. This continuous appreciation and respect for the craft makes him one of Hollywood’s most imaginative and admirable filmmakers working today.