Hugh Bonneville who plays Lord Grantham, shared a photo on Twitter of the cast posing for an informal group shot under a New York subway 'Downtown' sign.
The tiered floor-length open-fronted dress revealed the star's bra and her sky-high platform heels as she teetered through the city's Vnukovo airport.
The 31-year-old socialite opted for the odd colourful top, which featured two tiny pieces of fabric across her breasts to conceal her modesty.
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The heavily buckled heels trailed all the way up the actress's legs to her thigh and featured cut-out detailing at the knee.