Sienna Miller has been topping best dressed lists for the past few years - ever since she first stepped out on the arm of former beau Jude Law. Perhaps more famous for her fashion than her film roles, she's cultivated a unique personal style, and has been credited with kick-starting the boho trend a few years ago. Now more accustomed to gracing the red carpet in Gucci, Chloe and Peter Pilotto, she's also one half of Twenty8Twelve, which she designs with her sister Savannah.

Picture: At The Moet & Chandon Etoile Award for Mario Testino, Sienna dazzles in this gorgeous floor-length white dress with scalloped beading detail. With that dark red lipstick and her kohl-lined eyes, she looks stunning.

Sienna has quite the penchant for white - often flaunting her tan and long blonde locks in creamy creations. She goes for a Victoriana style here with the high lace neck and collar, but the short length and edgy ankle boots ensure she still looks edgy.

Another red carpet appearance and this time Sienna opts for another floor-sweeping gown in cream and silver.The lace top with it's long sleeves gives the otherwise simple, silk dress a somewhat unusual futuristic feel. She looks like a space age Guinevere, and we love it.

Fitting for a film premiere in Los Angeles, Sienna goes for an old-school Hollywood look, all Veronica Lake waves, scarlet lips and glitzy gold gown for the latest screening of G.I. Joe: The Rise Of Cobra.

Spotted out and about in New York looking ravishing in a red dress, black Chloé heels and sunglasses.

For the Japanese premiere of her latest film she chose to wear head-to-toe Gucci in a sequinned trouser suit and blouse.

At the London photocall for G.I. Joe wearing a white military-style blouse, navy trousers with brass buttons and slingback shoes, all by Loewe.

Leaving a New York hotel in a black Stella McCartney dress and matching heels.

Another premiere, another outfit. This time a graphic print mini dress by Diane von Furstenberg in Seoul, South Korea.

Heading to an American television studio for an appearance on The Early Show in New York wearing a multi-coloured polka dot dress by Diane von Furstenberg.

At a press call for her latest film in Sydney, Australia, wearing a floral print shirt-dress by Poltock & Walsh and suede lace-up boots by Chloé.

Making a television appearance on BET's 106 & Park in New York wearing a green Peter Pilotto dress and Isabel Marant ankle boots.

At a photocall for G.I. Joe in Berlin, wearing a grey jersey vest by Kain Label, black peg trousers, leopard print scarf, bangles and dark green heels by Chloé.

Another New York sighting, this time at the Gramercy Park Hotel wearing a black lace Topshop vest over a blue top teamed with animal print trousers, sunglasses and perspex and leather heels.

Making her way to an appearance on the Today Show in the United States wearing a silver beaded top, black tulip skirt and gold peep toe shoes, all by Derek Lam.