A denim jacket is one of the most versatile layering pieces in fashion. This guide covers five styling rules that always work, a full dos and don’ts section, and 20 celebrity and screen-inspired outfit ideas for men and women from Ryan Gosling’s Barbie denim vest to Timothee Chalamet’s Knicks courtside look, America Chavez’s screen jacket, and Jung Kook’s Calvin Klein denim look.