Looking impeccable (and not entirely unlike Gillian Anderson) Kate is modelling clothes from the St John collection for photographer Craig McDean and, in the words of creative director George Sharp:
"[Kate's] continued support in the brand and women's receptiveness to her beauty and extraordinary body of work are just some of the reasons to continue on with our relationship and decision to work together for our Spring 2012 Ad campaign."
Sounds like Ms Winslet has made some very fashionable fans!
To find out why Kate's so enthusiastic about the brand, just hit play on the video below:
And if these ads have you thinking about your 2012 wardrobe, just check out the gallery below for our new year style resolutions: