Blair has been shot by Chanel's chief designer Karl Lagerfeld for the series of print ads promoting the the fashion house's new range of sunglasses, Chanel Vision.
Blair, who also starred in 'The Sweetest Thing' alongside Cameron Diaz, is frequently snapped wearing Chanel frocks and even chose Lagerfeld to design her wedding dress last year.
She also confesses to be a fan of the enigmatic designer and photographer.
"I have a lovely relationship with Karl. It's different to be shot by him. I'm so comfortable in front of him. Sometimes when I work with other photographers, they say, 'Give me more Selma, more, more.'
"But they don't really know who I am. With Karl, he's capturing something that's more -- my personal flaws, the way I am as a girl, not a model," the actress told Women's Wear Daily.
Blair is currently filming 'Purple Violets' with 'Saving Private Ryan' actor Ed Burns and 'Will and Grace' star Debra Messing.
The actress joins a long list of high-profile stars to feature in Chanel campaigns including 'Moulin Rouge' and 'The Others' star Nicole Kidman, who was the face of Chanel No 5 in the most expensive ad to date, directed by Baz Luhrmann, and supermodel Kate Moss.
The Chanel Vision ads are to be unveiled next year.
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