Man cleavage -- plunging necklines slit open to reveal chest hair, pectoral muscles, maybe more -- is back.

Until recently, male décolletage was an androgynous fashion affectation limited mainly to sporadic appearances on European runways. But the look, including deep V-necks and scoop-neck tops, hit the U.S. in full force at New York's September Fashion Week, turning up at shows by Duckie Brown, Michael Bastian and Yigal Azrouël.

This time around, the styles were more blatantly sexual and the models had a more studly swagger. New York designer Mr. Bastian said his show's vibe was inspired in part by "Latin guys" he noticed wearing their shirts unbuttoned, as well as the unabashed machismo of Latin American men in general. "We wanted to go back to a more natural body, a more '70s body with the models, getting away from the super skinny," says Mr. Bastian.

Plenty of men, from regular Joes to "Dancing With the Stars" contestants, have loosened to the trend.

On HBO's hit series "True Blood," 29-year-old ex-model Mehcad Brooks rarely went an episode without removing his shirt. Mr. Brooks also frequently displays his perfect pecs off-screen, wearing rib-hugging T's with deep V-necks or shirts with the top buttons suggestively undone.