Sienna Miller channels boho-chic in a cream maxi dress

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Known for her effortless boho style, Sienna Miller was captured looking radiant in a flowy cream maxi dress at the US premiere of Horizon: An American Saga - Chapter 1 on Monday (24 June).

The actress has recently been providing us with a host of festival outfit inspiration, with her new summer collaboration with Marks & Spencer launching only this month, and her latest red carpet looks channeling her iconic free-spirited style.

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Nailing festival fashion in true style, Sienna is the queen of wearing frilly, bohemian looks teamed with stylish cowboy boots or ankle boots.

Steve Granitz

While most festivals in the UK are known for their unpredictable weather, our Fashion Director Amanda Marcantonio believes a pair of sturdy yet chic wellies or boots should be a must-have in your festival wardrobe this year.

She says: "Practical dressing can still be glam if you team function with fashion. Make sure your outfit is not 100% practical, otherwise you will look incredibly boring - festivals are all about having fun, so add some frivolity via a playful skirt, swishy midi/maxi or a ruffle blouse - 'high-low' styling feels effortlessly modern in my eyes."

If you're wanting to replicate Sienna's iconic maxi dress moment this summer, we've find our favourite high-street alternatives below: