Sisters Savannah and Sienna Miller lend style to high street brands

<span>Photograph: Dave Benett/Getty Images</span>
Photograph: Dave Benett/Getty Images

A pair of fortysomething British sisters – one a Hollywood star, the other a Central Saint Martins-trained designer with a 20-year career in fashion – are spearheading a resurgence of high style on the British high street.

Sienna Miller is the face of Marks & Spencer, where the oversized lime knitwear and Westwood-esque fluffy tartan coat seen in her advertising campaign is taking pride of place on shop floors. The signing reflects a new confidence at M&S, where sales of clothing and homewares rose 6% in the first quarter of this financial year.

The Golden Globe-nominated actor goes head to head with her older sister this season, as Savannah Miller, who began her career at Alexander McQueen and Matthew Williamson, launches Vivere, an affordable tailoring label, which has been snapped up by John Lewis.

Sienna and Savannah Miller stand in front of a poster of themselves
Sienna and Savannah Miller launch their Twenty8Twelve collection in 2011. Photograph: Stefan Wermuth/Reuters

Savannah denies any sibling rivalry, insisting she is “absolutely delighted to have my sister in the UK again, after her living in America for so long. And I’m happy to see M&S making a comeback. Having Sienna’s electric charisma is so great for them.” The sisters, who jointly launched the Twenty8Twelve label in their 20s and co-designed it for five years, “have always talked about fashion and still do”, says Savannah. “Mostly, like all sisters, we just gossip. I said to her the other day, please can you text Anna Wintour and ask her when Phoebe [Philo] is coming back and who’s going to take over when Sarah Burton leaves [Alexander] McQueen?”

“Sienna sells,” says Hattie Brett, the editor-in-chief of Grazia magazine. “The British shopper has grown up with Sienna, so there’s a familiarity there. And she has the style that British women – perhaps unlike their European counterparts – crave, which is that she looks great without looking like she’s tried too hard. Effortless is an overrated word, but Sienna nails it. And Savannah is very clever and knows exactly who she’s designing for, so I’m intrigued to see Vivere. Chic, affordable workwear is a category so many retailers can’t seem to get right.”

Savannah Miller wearing a floral dress stands in front of a retail counter
Savannah Miller at the launch of the Nobody’s Child pop-up shop in Carnaby Street in 2021. Photograph: Dave Benett/Getty Images

With pop culture in the grip of Y2K nostalgia, the Miller sisters stand for the spirit of an era of which many British shoppers have fond memories. Sienna was the poster girl for “boho chic” at a time when British fashion led the world, while the Twenty8Twelve label was a staple of festival-goers’ wardrobes during the years when Glastonbury became a style phenomenon and “festival style” a mainstream fashion category. A boho-chic “Julie” faux-shearling soft cream waistcoat is among Vivere’s best-selling pieces at John Lewis. Beth Pettet, the head of fashion brands for John Lewis, describes Savannah as “the perfect fit for John Lewis, as she has that quintessential British style”.

Cosy faux-shearling is also a hit at M&S, where a £79 chocolate brown aviator-style jacket included in Sienna Miller’s edit of favourite pieces has been a bestseller. The womenswear director, Maddy Evans, reports that the Sienna signing has led to “sentiment reaching an all-time high” at M&S and customer feedback that the collection feels “relatable with easy styling options that feel really inclusive”.

Celebrity endorsement “helps create stories that get cut-through” in a crowded fashion market, says Brett. Rita Ora recently launched a range for Primark with a starry London fashion week party, while Naomi Campbell has designed a collection for Pretty Little Thing. Collaborations with women seen as style leaders, whether designers or celebrities, are popular with busy, time-poor shoppers. “Having Sienna seek out and style up the key pieces from M&S, a retailer that our audience loves but can sometimes feel overwhelmed by because of its scale” instantly appealed to Grazia readers, Brett adds.

A capsule range by the ex-Givenchy designer Clare Waight Keller is bringing an influx of fashion-forward consumers to Uniqlo, with the distinctive rose-pink of the £39.90 Corduroy Wide Leg Trousers making several appearances on the Paris fashion front rows this week. Jigsaw, which under its creative director, Jo Sykes, has come back into the spotlight, is about to announce a collaboration with an as-yet-unnamed star of London fashion week next month.

Savannah Miller, who has previously designed for Debenhams and Next, decided to step back into creating ready-to-wear fashion alongside her successful bridal line to fill what she sees as a gap in the existing high street offer. “For my job I have to do lots of trade shows, which are long days when I’m on feet and trying to present my best self, and I figured out that I needed a uniform for that. I bought high street trouser suits but the construction just wasn’t proper tailoring and pretty soon they were falling apart. You can buy beautiful suits for £700, but who has that kind of money? I don’t.”

Vivere is produced in Turkey and aims to be “a responsible brand – it’s not just about the fabric you use, it’s things like the hours that people who work for you are doing”, she says. “I believe there are lots of women out there like me, who want clothes that have a bit of a point of view but aren’t intimidating or uncomfortable. I always put a little section of elastic in the back waistband of trousers, where you can’t see it. It just gives you that bit of forgiveness after lunch.”

The key pieces to snap up

Classic double breasted black blazer, £69, M&S

Lula cigarette trousers, £120, Vivere at John Lewis

Vegan leather loafers in classic deep brown, £39.90, Uniqlo C