Sienna Miller’s Top 5 Style Rules

[tiImage width=”300″ height=”400″ url=”” credit=”Juan Rico/Fame” align=”left” border=”1″ alt=””]Happy birthday, Sienna Miller! In honor of the trendsetting actress’s 29th birthday today, we took a look back at her style to pinpoint her top five style rules. Who can’t learn a thing or two from this red carpet master? Click through to see Sienna Miller’s top go-to styles. Plus: Tell us what you think of her style in the comments!

Everyone Is Shopping This Week!

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‘Tis the week for shopping! Some of our favorite celebrities are out and about cramming in some last-minute holiday purchases, including Sienna Miller, who was spotted carrying bags from Heidi Klein and Zadig & Voltaire in London today. See more holiday shoppers, from Jennifer Garner to Rihanna to Reese Witherspoon, in the gallery.

Check out InStyle‘s Holiday Gift Guide!

Bell, Hudson, Miller and Kardashian Stay Cozy in Cape Coats

[tiImage width=”623″ height=”400″ url=”” credit=”Credit – Ringo/; Bryan Bedder/Getty; Danny Martindale/FilmMagic; James Devaney/WireImage” align=”center” border=”1″ alt=””]Kristen Bell stayed warm while promoting her new movie Burlesque in chilly London this week wearing an ivory cape coat by designer Vanessa Bruno. “I personally have long been a fan of capes,” Bruno told InStyle. “Worn with a great boot, it’s always been a chic silhouette for any woman. I love the dramatic versatility of this ivory piece and the way it can really make its mark from day to night. This one, a wool-angora mix, is a cozy winter wardrobe staple.” Other celebrities agree: Kate Hudson wore a gray and black cape coat by Louis Vuitton a few months ago, Sienna Miller recently stepped out with a red one draped around her shoulders and Kim Kardashian tried a cream cape with black trim by 3.1 Phillip Lim this fall.

Matthew Williamson on His New Bridal Collection

[tiImage width=”300″ height=”400″ url=”” credit=”Gareth Cattermole/Getty” align=”right” border=”1″ alt=””]Matthew Williamson is launching a bridal collection, and we caught up with the British designer to find out the details: “I evolved the bridalwear from the soft femininity and luxurious aesthetic found within my runway collections each season,” the designer (shown with celebrity fan Sienna Miller) told InStyle exclusively. “The pieces will offer an extensive range of options—classic silhouettes to entice both the boho, glamourous brides-to-be and the more structured, modern brides alike.” The line, which Williamson tells us will feature silk gowns with embellishments and several accessories, will be sold at the Matthew Williamson flagship store in New York starting next year. We can’t wait to see it!

Matthew Williamson’s diffusion line drops next fall
See celebrities in Matthew Williamson

2010's Top Celebrity Fashion Trends!

[tiImage width=”623″ height=”400″ url=”” credit=”INF photo; Pascal Le Segretain/Getty; Jon Kopaloff/FilmMagic” align=”left” border=”1″ alt=””]What was your favorite trend of 2010? Did you slip into a slim-fitting pair of tailored trousers, like Drew Barrymore? Did you pair your coziest socks with your sexiest heels, like Leighton Meester? Or maybe you took your short shorts from the gym to the office, like Gwyneth Paltrow. We’ve scoured the red carpets to round up the best fads of the year. Click through our gallery to see which celebrities jumped on the trend wagon—and which styles you were savvy enough to rock yourself!