Ronan joined the French luxury fashion house as an ambassador last January.

Saoirse Ronan, Blitz, London Film Festival, Louis Vuitton white dress

LONDON, ENGLAND - OCTOBER 13: Kieran Culkin and Jazz Charton attend the "A Real Pain" Special Presentation during the 68th BFI London Film Festival at The Royal Festival Hall on October 13, 2024 in London, England. (Photo by Lia Toby/Getty Images for BFI)

LONDON, ENGLAND - OCTOBER 13: Cate Blanchett attends the "Rumours" screening during the 68th BFI London Film Festival at BFI Southbank on October 13, 2024 in London, England. (Photo by Tristan Fewings/Getty Images for BFI)

LONDON, ENGLAND - OCTOBER 13: Pedro Pascal attends "The Wild Robot" Headline Gala during the 68th BFI London Film Festival at The Royal Festival Hall on October 13, 2024 in London, England. (Photo by John Phillips/Getty Images for BFI)

LONDON, ENGLAND - OCTOBER 13: Nikki Amuka-Bird attends the "Rumours" screening during the 68th BFI London Film Festival at BFI Southbank on October 13, 2024 in London, England. (Photo by Tristan Fewings/Getty Images for BFI)

Saoirse Ronan hit the red carpet on Wednesday for the premiere of her forthcoming film “Blitz.” The World War II epic, directed by Oscar winner Steve McQueen, held its world premiere during the 2024 London Film Festival.

The four-time Academy Award-nominated actress wore a custom dress courtesy of Louis Vuitton. The sleeveless gown featured a white crêpe jersey high-neckline with white leather studded belt detail at the hips and waist that criss-crossed.

Saoirse Ronan, Blitz, London Film Festival, Louis Vuitton

Saoirse Ronan attends the “Blitz” premiere during London Film Festival 2024 on Oct. 9. JOE MAHER/GETTY IMAGES FOR BFI

The floor-length dress added to Ronan’s angular look, with her hair slicked back in a tight chignon. The actress opted for little-to-no jewelry, save for one ring. Her makeup featured bold brows and a slight hint of a smokey eye, along with a rosy lip.

The actress was named an ambassador to the French luxury fashion house last January. “I have admired Saoirse’s career for many years now; I find her totally captivating in the roles she plays,” said Nicolas Ghesquière, Louis Vuitton’s artistic director of women’s collections. “What’s more, behind her talent lies such a charming and bright person.”

Saoirse Ronan, Blitz, London Film Festival, Louis Vuitton

Saoirse Ronan attends the “Blitz” premiere during London Film Festival 2024 on Oct. 9. JOE MAHER/GETTY IMAGES FOR BFI

Since her ambassadorship appointment, Ronan has worn Louis Vuitton for several high-profile, red carpet occasions. The actress wore a dress with semi-sheer elements to the Emmy Awards last September.

For the premiere of her film “Outrun,” in which she stars and coproduces, Ronan opted for a design from the French luxury fashion house’s cruise 2025 collection. The vibrant blue minidress featured an asymmetrical neckline and a bubble hem.

Saoirse Ronan, Blitz, London Film Festival, Louis Vuitton

Saoirse Ronan attends the “Blitz” premiere during London Film Festival 2024 on Oct. 9. JOE MAHER/GETTY IMAGES FOR BFI

Directed and written by “12 Years A Slave” filmmaker Steve McQueen, “Blitz” follows a group of Londoners during the capital bombing of World War II. The film costars Elliott Heffernan and Harris Dickinson. “Blitz” releases in theaters Nov. 1, followed by its Apple TV+ debut on Nov. 22.