Sienna Miller Just Wore the Casual Errand Outfit That I'm Copying This Weekend

There are some age-old styling conundrums that come back around year after year, decade after decade that we still struggle to answer. "What do I wear to a wedding?", "what do I wear to work?", and "how do I dress up jeans?" being the most common (and somehow the answer always ends up being a "nice" top), but there is one scenario in particular that I'm almost certain you've never asked out loud but have always wanted to know the answer to: "What do I wear to run errands?"
You see, TikTok has attempted to answer the question, and people in their thousands are flocking to see the response. After all, we're all familiar with the scenario. The weekend rolls around and your to-do list is growing in length, so you need an outfit that is both "throw-on and go" and effortlessly stylish, so what exactly does one wear that will look as good doing a food shop as it will meeting your friends for brunch? Well TikTok, I think I just found the answer, and it comes courtesy of Sienna Miller.
Most will not be surprised that Sienna has served as our fashionable inspiration yet again. After all, she recently revived the cargo jean, showed us how to take the maxi skirt into evening territory, and set the tone for all bridesmaid dresses this year, but it's her latest dressed-down look that is ticking all of our boxes.
Perhaps taking notes from the 2X2 outfit formula (that I promise you, always works,) Sienna's anti-jeans, pro-tailoring weekend outfit is not only a masterclass in high/low dressing, but is also the perfect outfit to wear with trainers. Maybe it's the tonal, grey colour palette, maybe it's the well-cut, boxy blazer, it could even be the relaxed, straight-leg trouser, but something about the combination of all three works, and gives us a laidback outfit that's incredibly easy to replicate. So, wondering what to wear this week? I've reconstructed Sienna's outfit below, so you can wear it for work, the weekend and everything in between. You can think me later.
SHOP SIENNA MILLER'S BLAZER AND TRAINERS LOOK:
Until we can find the exact jacket Sienna is wearing (and we're keeping our eyes peeled!), this is an excellent lookalike from one of her preferred high-street brands.
When it comes to quality basics, there's no better place to start than Arket.
You're going to have to be quick off the mark to snap these up before they sell out. Again.
SHOP MORE BLAZERS
If you're looking for an exaggerated silhouette, it has to be The Frankie Shop.
Every wardrobe should have a good black blazer. It might just be the most versatile piece you can own.
SHOP MORE TAILORED TROUSERS
Technically a wide leg as opposed to straight, but these would be so chic with a t-shirt and trainers.
The Mason pant we know and loved is now in a cropped style to show off your shoes.
SHOP MORE TRAINERS
Name a sharper pairing than a tailored trouser and an all-white trainer. I'll wait...
Fashion people agree, Loewe accessories are worth investing in.
Chic, simple, understated.
Bored of white but need a trainer that will go with everything? Try refined brown suede.
Up Next, The 8 Chic Alternatives I Go to When I Don't Feel Like Wearing Jeans
Remy Farrell is a London-based fashion editor with 10 years of experience covering fashion, beauty and lifestyle. After graduating with a journalism degree and working on the fashion teams for titles such as Grazia, Elle, and British Vogue, she moved into the luxury e-commerce sector, working as fashion assistant at TheOutnet.com After expanding an assisting and styling portfolio that includes talent such as Gigi Hadid, Victoria Beckham and Miquita Oliver, she ventured into beauty, compiling reviews and diverse beauty content. In her role as fashion editor at Who What Wear, Remy is interested in discovering new brands to share with the WWW UK readership, and loves uncovering hidden gems to make shopping accessible to everyone.
-
I Just Created 5 Expensive-Looking Pre-Spring Outfits from Zara, Mango, and Nordstrom—You're Welcome
Outfits for everything from a wedding to brunch.
By Nikki Chwatt
-
Sunscreen Filters Abroad Are Totally Elite—Here's Why They're Not Available in the U.S. Yet
It's a bummer, but I have hope.
By Shawna Hudson
-
I Already Have an Elevated Closet, But If I Were to Start Over, I'd Go for These 5 Staples
Effortless outfit ideas ahead.
By Jennifer Camp Forbes
-
The 2025 It Girl's Wardrobe: 9 Highly Specific Brands and Buys They're All Wearing
From handbags to jeans to jewelry.
By Anna LaPlaca
-
If a French Woman Shopped the Gap and Banana Republic Sales, These 30 Chic Picks Would Catch Her Eye
Oui, merci!
By Jennifer Camp Forbes
-
5 Simple Yet Striking Basics That You'll Wear for Many Years Are All at Nordstrom
These will instantly elevate your wardrobe.
By Jennifer Camp Forbes
-
6 Elegant Blazer Outfits All the Cool European Women Are Wearing
They've got the right idea.
By Natalie Cantell
-
I'm High-Key Obsessed—Nordstrom Has the Best Basics, and They're on Sale
Top-tier pieces ahead.
By Chichi Offor
-
Kendall Jenner Landed in Paris and Ditched Black Blazers for These Stylish Alternatives
Upgrade.
By Eliza Huber
-
Jennifer Lawrence Just Wore the Jacket Trend French and Italian Women Swear By to Look Elegant
It works every time.
By Eliza Huber