Sienna Miller highlights her lean physique in loose-fitting satin gown as she forgoes a bra for High-Rise premiere in San Sebastian

Just 24 hours earlier she was covered up in a thick, woolly coat at the Burberry show during London Fashion Week.

But actress Sienna Miller, 33, ensured her slender frame was on full display as she stepped out for the High-Rise premiere in San Sebastian, Spain on Tuesday evening.

The mother-of-one was seen in a loose-fitting satin frock as she hit the red carpet at the Kursaal Palace during the 63rd San Sebastian International Film Festival.

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Lean physique: Actress Sienna Miller, 33, ensured her slender frame was on full display as she stepped out for the High-Rise premiere in San Sebastian, Spain on Tuesday evening

Lean physique: Actress Sienna Miller, 33, ensured her slender frame was on full display as she stepped out for the High-Rise premiere in San Sebastian, Spain on Tuesday evening

The British beauty donned a scoop-neck, copper satin Galvan gown which skimmed her svelte frame, leaving little to the imagination as she opted to go bra-less for the occasion.

Sienna also appeared to have a slight mishap with the frock as, when the vintage-inspired gown sweeped the floor, the hem got soaked on the red carpet and she was seen trying to lift it up.

However, ever the professional, she carried on regardless, looking stunning in her lovely dress which was teamed with a delicate gold chain.

Promo trail: The mother-of-one was seen in a form-fitting satin frock as she hit the red carpet at the Kursaal Palace during the 63rd San Sebastian International Film Festival
Beauty: Sienna looked stunning in her lovely dress which was teamed with a delicate gold chain

Promo trail: The mother-of-one was seen in a form-fitting satin frock as she hit the red carpet at the Kursaal Palace during the 63rd San Sebastian International Film Festival

Metallic: The British beauty donned a scoop-neck, copper satin Galvan gown which skimmed her svelte frame, her nipples on display as she opted to go bra-less for the occasion

Metallic: The British beauty donned a scoop-neck, copper satin Galvan gown which skimmed her svelte frame, her nipples on display as she opted to go bra-less for the occasion

Channel Sienna's minimal style in her Galvan slip dress

Sometimes less is more and Sienna Miller proved this to be true when she arrived on the red carpet at the San Sebastian Film Festival in a Galvan slip dress.

The American Sniper star wore her blush toned gown with nothing but a long necklace, a slicked back bun and red lipstick.

We're all for the usual sequins, prints and embellishments that celebrities usually wear to big events, but Sienna's minimalist look eschewed all of the frills for a modern and refreshing sight.

This exact look is not available, but click right to get a similar style at Matches Fashion. Then head down to the carousel below for our alternative selections - all budgets covered.

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Seen animatedly taking selfies with fans, the American Sniper star sported a beautiful make-up look consisting of a dewy complexion and berry-stained lips, in addition to a wet-look bun.

Her tattoo of three miniature stars was also visible on her right shoulder.

The ex-fiancée of fellow actor Tom Sturridge, with whom she shares a daughter, Marlowe, posed alongside her High Rise co-stars Tom Hiddleston and Luke Evans.

Awkward: Sienna also appeared to have a slight mishap with the frock as, when the vintage-inspired gown sweeped the floor, the hem got soaked on the red carpet and she was seen trying to lift it up

Awkward: Sienna also appeared to have a slight mishap with the frock as, when the vintage-inspired gown sweeped the floor, the hem got soaked on the red carpet and she was seen trying to lift it up

Taking time out: The American Sniper star was seen animatedly taking selfies with fans

Taking time out: The American Sniper star was seen animatedly taking selfies with fans

The Avengers actor Tom showcased his classic style, wearing a fitted navy suit with a white shirt, burgundy tie and black leather brogue shoes.

Luke Evans, meanwhile, went for a slightly quirkier look in a blue check three-piece suit, worn with a grey tweed tie, white shirt and brown suede shoes. 

Sienna's demure look came after the star rocked a more casual ensemble to the movie's press conference earlier in the day. 

The Factory Girl star reiterated her style credentials in a knitted red sweater and a coordinating knit midi-skirt, her glossy tresses worn tousled around her pretty face.

The film, directed by Ben Wheatley, tells the story of residents of a tower block, whose lives start to spiral out of control.

British beauty: Sienna sported a beautiful make-up look consisting of a dewy complexion and berry-stained lips

British beauty: Sienna sported a beautiful make-up look consisting of a dewy complexion and berry-stained lips

Sleek: The actress sported a wet-look hairstyle
Tat lover: Her tattoo of three miniature stars also visible on her right shoulder

Sleek: The actress sported a wet-look hairstyle, her tattoo of three miniature stars also visible on her right shoulder

Leading men: The actress posed alongside her High Rise co-stars Tom Hiddleston and Luke Evans

Leading men: The actress posed alongside her High Rise co-stars Tom Hiddleston and Luke Evans

Lady in red: Sienna's demure look came after the star rocked a more casual ensemble to the movie's press conference earlier in the day

Lady in red: Sienna's demure look came after the star rocked a more casual ensemble to the movie's press conference earlier in the day

Sienna plays the leading lady, Charlotte Melville, in the movie which is scheduled for a 2016 release.

The stellar ensemble piece also stars Jeremy Irons, Elisabeth Moss, James Purefoy and Keeley Hawes.

Meanwhile, Sienna recently admitted she turned down a major role on Broadway after finding out her male co-star was going to be paid more.

Bold: Luke Evans went for a blue check three-piece suit, worn with a grey tweed tie, white shirt and brown suede shoes

Bold: Luke Evans went for a blue check three-piece suit, worn with a grey tweed tie, white shirt and brown suede shoes

Fashionista: The Factory Girl star reiterated her style credentials in a knitted red sweater and a coordinating knit midi-skirt

Fashionista: The Factory Girl star reiterated her style credentials in a knitted red sweater and a coordinating knit midi-skirt

She told Vogue: 'It was a play with just two of us on stage and I was offered less than half of what he was going to be paid. If it was two men, it wouldn’t probably happen. Sad, but I walked away.

'The producer… wouldn’t pay me within a million miles of what the male actor was being paid. And women always have to do more publicity than the men.

'The only way is to make a stand. We are going to have to make sacrifices to make change. I want to turn up and feel dignified.' 

Pals: The stars appear in High-Rise, a film directed by Ben Wheatley which tells the story of residents of a tower block, whose lives start to spiral out of control

Pals: The stars appear in High-Rise, a film directed by Ben Wheatley which tells the story of residents of a tower block, whose lives start to spiral out of control

Effortless: The actress rocked a more natural make-up look and styled her hair into edgy tousled waves during the earlier press conference
Effortless: The actress rocked a more natural make-up look and styled her hair into edgy tousled waves during the earlier press conference

Effortless: The actress rocked a more natural make-up look and styled her hair into edgy tousled waves during the earlier press conference

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