Sienna Miller signals the start of coat season in the high street style you'll wear with everything this autumn
She finished her chic look with Monica Vinader jewellery
It might still feel warm, but Sienna Miller just confirmed that coat season is on its way. She stepped out to promote her new Sky Original series WAR, wearing a smartly tailored coat from Mango that looks far more expensive than its high street price tag.
The structured, sophisticated style is exactly the kind of layer you'll want to wear with everything from jeans and comfortable trainers to dresses and knee-high boots. And while it might feel early to be putting all your winter coat eggs in one basket, now that Sienna has worn this £230 style, I'd expect it to sell out very soon.
The star kept the rest of her look understated yet incredibly sophisticated, wearing a blue shirt and wool trousers - both of which are also from Mango - adding some gold jewellery by Kate Middleton-approved jewellery brand Monica Vinader to complete the look.
Shop the coat
Available in sizes XS to L, this coat features a classic blazer-style lapel and button fastening. It will look incredibly polished worn with a party season LBD or workwear, but what I really love about this coat is that it will sharpen up more laidback looks, too. The longer length feels very grown-up, and I'm taking notes from Sienna, having the shirt cuffs peeking out. It's actually a very dark grey colour, which is a slightly softer alternative to black, and will work with all the autumn/winter fashion colour trends 2026.
Complete the look
This shirt is from Mango's new selection collection, which is full of premium pieces that won't date. It's the perfect shade of blue, and would work beautifully with camel or tomato red tones as well as more neutral outfits.
These straight-cut trousers are 100% wool, which will keep you warm when the temperatures really drop. They're a very chic alternative to jeans if you're bored of wearing denim on repeat.
You simply cannot go wrong with some subtle gold jewellery, and this necklace is a style you'll find yourself wearing all day, every day. You can adjust the length, so you can wear it with lots of different necklines.
If you're already thinking about Christmas presents, this would make someone very happy on 25th December. The sculptural design is absolutely mesmerising.
You might recall Sienna wearing a navy wool coat by ALIGNE, which became a hugely popular piece with shoppers last year, and there's no reason to think the same won't happen with the Mango coat.
It's well worth investing as much as you can in a coat, and even though £230 might be a bit more than you might expect to spend on the high street, it's made from a cotton and wool blend fabric that feels as luxe as it looks. Don't forget, as well, that with a versatile style like Sienna's coat, you really will wear it every day throughout autumn and winter, so if you consider the cost per wear, it's a no-brainer.
If you've been waiting for your cue to start coat shopping, consider Sienna's look to be a sign. Stick to a classic style that will be a wardrobe workhorse right through to spring, and it will make dressing for the colder weather a breeze.
