Sienna Miller Looks Ethereal In A Breezy White Dress And Leather Boots For Premiere Of Her New Drama With Kevin Costner

Sienna Miller dazzled at the premiere of her latest Western film, Horizon: An American Epic: Chapter 1 , where she stars alongside Kevin Costner (also the film’s director and co-writer).

The Golden Globe-winning actress, 42, turned heads in a boho chic spaghetti strap dress adorned with intricate lace and ruffle accents, complemented by a flowing, tiered maxi skirt.

Sienna Miller Proves She's The Queen Of Boho Chic In Elegant White Lace And Ruffle Gown

To complete her stunning look, Miller wore black leather pointed-toe boots, a striking gold statement necklace, and a collection of layered gold charm bracelets.

The stylish Factory Girl star wore her signature blonde tresses down, parted in the center and styled into effortless loose waves.

As for her makeup look, the mom of two (who shares daughter Marlowe , 11, with ex Tom Sturridge and a six-month-old daughter with current boyfriend Oli Green ) sported subtle black liner, voluminous lashes, rosy blush and a natural pink pout.

Horizon: An American Saga – Chapter 1 is an epic Western film that Costner, 69, not only directed and produced but also starred in.

The screenplay, co- written by Costner and Jon Baird , is based on an original story they crafted alongside Mark Kasdan. This film (starring Miller as Frances Kittredge and Costner as Hayes Ellison) marks the beginning of the Horizon series. It made its debut at the 77th Cannes Film Festival on May 19th before hitting theaters across the United States on June 28th.

The saga continues with Chapter 2, set for release on August 16th. Meanwhile , Chapter 3 commenced filming last month, and Chapter 4 is currently in the works .