D enim shirts are a closet mainstay and are carving out an ever-bigger presence in the outfits of fashion insiders this year.

From tailored, dark denim trousers to worn-in ... an oversized button-down, crewneck T-shirt, and relaxed wide-leg jeans. The result? One winning outfit—no effort required.

Until, that is, the recent fashion week circuit kicked off and denim became quite the statement-making style. Fendi stuck to structured denim two-pieces, Diesel delivered oversized denim shirts ...