If my time in the fashion industry has taught me anything, it’s that when Sienna Miller backs something, it won’t be long until it becomes a cult-worthy buy. So this week, as the actor stepped out for one of her many press appearances for her film War, she put me onto a jacket trend I’m now convinced will be everywhere soon.

Stepping away from her usual boho sensibilities, Sienna opted for a sleek, modern look, championing a leather jacket silhouette I think is about to take off. Her cinched-waist style featured strong shoulder pads, a glossy leather finish and a broad collar that borrowed from the traditional biker jacket silhouette.

Styling Balmain’s Signature Leather Jacket (£3590) with the French label’s Low-Waisted Wool Satin Trousers (£1090), Sienna’s all-black look created a sleek, wearable foundation that let the details of each piece shine. The jacket’s cinched waist, for example, created a contoured silhouette, bringing shape and elegance to her otherwise unfussy outfit.

Whilst a black leather jacket will never go out of style, each season tends to bring a fresh take on the classic silhouette. For autumn/winter 2026, oversized proportions, cinched waists and strong shoulders are the details to know.