New York • Clothes are a key part of weddings — and, it turns out, the marriage of art and commerce.

Katie Holmes, Josh Duhamel and Malin Akerman are among the well-dressed stars of the upcoming film "The Romantics," which is all about friends reuniting for a wedding while still nursing a few wounds still not healed. Here, fashion isn't just playing a supporting role — it's a key marketing partner for the film.

The cast, which also includes Adam Brody, Rebecca Lawrence and Jeremy Strong, reunited recently for a photo shoot for J.Crew and changed in and out of several outfits over the course of several hours for the retailer's fall catalog and the brand's website.

Holmes wore black-sequin harem pants paired with a chambray button-down shirt, a combination she likes because it's "a little more tomboy, a little Diane Keaton," as well as a brown cocktail frock and a champagne-colored, flapper-inspired beaded number. That one was her favorite, Holmes says: "It's flirty but grown-up, too."

The vast studio in Chelsea marked a new sort of crossroads for fashion and film. "The Romantics" and J.Crew don't just dabble in product placement — although some of the costumes were indeed J.Crew. The retailer is serving as a bona fide marketing partner, including covering the costs associated with the shoot.

In the film, the characters largely are introduced through their wardrobes: the flirty girl in a studded mini; the pensive but pretty one wearing things dark and demure; the bride obviously in white, even for the rehearsal dinner, as if to say, "Remember, I'm the bride here." The guys are in untucked shirts with suits and ties, not truly ready to part with their youthful ways.

"Because the story is about a group of 20-something-year-olds and before they've really become 'adults,' clothes are a huge part of defining their identity," says director Galt Niederhoffer. "Clothes are a personal statement. They can break people visually into introverts, extroverts, romantics, geeks."

The looks were a mix of J.Crew's classics, bridal styles and the new 769 Collection.

Niederhoffer, on this day in head-to-toe Madewell, another J.Crew brand, doesn't shy away from the art and commerce connection. She says it might be what keeps small filmmakers going.