TO help a new campaign stand out in the crowded marketplace for apparel retailers, Banana Republic decided, among other things, to change ad themes, adopting “The true outfitters of modern American style,” and feature pairs of models who are also coupled up in real life — with a twist. Amid the stylish men and women wearing the new spring line for Banana Republic is a couple composed of two men, the interior designer Nate Berkus and his fiancé, Jeremiah Brent, who is also an interior designer.

In one ad, the pair is lounging on the grass, Mr. Berkus’s head on Mr. Brent’s midsection. In another ad, the couple is cuddling. In other ads, the pair appears among photographs of the other couples. In the magazines in which the campaign is now starting to appear, including InStyle and Rolling Stone, Banana Republic is the only clothier to present a same-sex couple amid the ad pages.

The point of the casting was not to be provocative, said Trey Laird, chief creative officer at Laird & Partners in New York, the MDC Partners division that was hired in November as the new creative agency for Banana Republic. Rather, the goal was “to reflect our world and how we live,” he said, “in a true, genuine way.”

“We create messages that sometimes are clever, but often there’s not a lot of reality to them; they feel set up,” Mr. Laird said. “Letting authenticity be our guide brings a lot of emotion into it.”