See Sienna Miller's Style Evolution Through the Years

Miller was the epitome of laidback cool in this drapey chiffon dress featuring a tie-dye print and flowy shoulder details. Her strappy red heels and minimal makeup complemented the look in every way.

The screen siren nailed the boho trend in the early 2000s when she arrived at a launch party in a lace-up black top, a suede jacket, and slouchy boots. Her studded belt and wavy tresses sealed the deal.

Whether she was in casual jeans and a tee to run errands or donning a gorgeous gown on a red carpet, Miller proved she could do and wear it all. For instance, her presence at the UK premiere of Cold Mountain was complete with a strapless silk gown, a knotted choker, and silver hoop earrings. It was simple yet elegant.

Often photographed out and about wearing neutral hues, Miller decided on a vibrant fuchsia dress for a Golden Globes party with then-boyfriend Jude Law in 2004. Her colorful look was accented with sparkly chandelier earrings and a sweet satin bow.

Miller kept the colorful gown trend going when she stopped by an Oscars party in a goddess-like teal dress punctuated with metallic gold details.

She even made the simplest of outfits look oh-so-cool. The star wore a raw-edge denim skirt, white tank, embroidered cowboy boots, and tinted shades while walking around Notting Hill. Her oversized red shoulder bag added a pop of color, whereas her simple necklace and bracelet offered the right amount of detail.

Miller was pretty in pink when she arrived at an early 2000s event in a striped, strapless gown with a full skirt and sweetheart neckline. Meanwhile, her metallic hair accessory added a touch of unexpectedness to the look.

She had her monochrome moment when she posed for photos at the Venice Film Festival in a black Roland Mouret minidress with an asymmetrical neckline paired with oversized sunnies. Her swept-back hair and simple gold jewelry offered elevated final touches.

Miller decided to go for gold in this fabulous sequined ensemble with a ruffled hem and strappy gold-toned heels. A studded black leather handbag contrasted perfectly with the show-stopping getup.

The Hollywood star wore another gold dress, this time to the Met Gala in 2006. Her fun frock, which she paired with sheer black tights and block heels, was designed by Burberry. In fact, she donned the show-stopping shift over 13 years later to another event.

Gray isn't often the first color choice for a gown, but Miller proved it's just as glamorous as other hues. When walking the Metropolitan Opera opening night red carpet, the actress glowed in this glittery dress featuring a floral fabric neckline and chiffon hem.

Miller sported a noticeably pared-down black ensemble several years later at a British awards ceremony. The clingy, long-sleeved gown boasted a floor-length skirt and a plunging neckline. Her red lips and head-turning chandelier earrings were glamorous touches that took things to the next level.

The British actress exuded sweet sophistication for a UNICEF charity gala in a delicate pink ombre gown accessorized with open-toed patent leather heels and a boxy clutch.

As Miller proved in this green-hued number, a dash of sequins goes a long way. Additional metallic details, such as those in her shoes and handbag, stepped the look up even more.

Miller made an appearance at the G.I. Joe: The Rise Of Cobra red carpet in a subdued gold gown with puffed sleeves and draped hem. Her deep side part and scarlet lipstick gave it a stunning vintage vibe.

Miller and Law always looked stylish together. For the 2010 Met Gala, the actress wore a beaded navy Emilio Pucci dress with a high-low hem, while Law sported a simple, yet sleek, black tuxedo.

Miller wore a timeless off-white mesh gown to a charity event in 2010. The look was unique and had a curved waistline.

Miller wore an elegant cream-caped gown to the Hamptons International Film Festival in 2012.

A year later, she rocked a demure pink long-sleeved silk minidress at the BAFTAs awards season tea party.

The actress wore a sleeveless Erdem gown with Giuseppe Zanotti heels to the 2013 Golden Globe Awards. It was reminiscent of earlier floral dresses she was often snapped in.