Sienna Miller at “Horizon: An American Saga – Chapter 1” Premiere in Los Angeles

Sienna Miller is set to captivate audiences as a lovelorn widow in Kevin Costner’s highly anticipated western, Horizon: An American Saga. The trailer showcases her wandering the expansive plains of Utah, adorned in ruffled saloon gowns, evoking a mix of forlornness and resilience.

At the film’s Los Angeles premiere, Miller dazzled in a silk charmeuse gown from Chloé’s spring-summer 2025 collection, complete with lace-trimmed inserts and calfskin boots. The look, reminiscent of a gun-twirling milkmaid, encapsulated a raw, pastoral beauty. The hem of her dress, haphazardly tucked into a boot, suggested a recent horseback dismount, blending elegance with rugged practicality.

Miller’s fashion choices are no accident. As a boho-chic icon, she has long been aligned with Chloé’s vision. She debuted on Chemena Kamali’s first Chloé catwalk in March and has since donned the brand at prestigious events like the 2024 Met Gala and Cannes Film Festival. These garments, designed for strong women, echo the spirit of the film’s heroine.

In Horizon, Miller’s character may face relentless hardship, but her style remains unwavering. Her portrayal, underscored by Chloé’s sophisticated yet tough designs, serves as a testament to the enduring appeal of fashion that marries grace with grit.