The campaign has been created in-house and will break next month. It will appear in the national press and supplements and was shot on the slopes of Chamonix in the French Alps.
Nemcova came to wider public attention in 2004, when she was caught up in the Boxing Day tsunami in Thailand. She survived but her photographer fiance, Simon Atlee, died. She has since campaigned for children affected by the catastrophe and written a book about her experiences, called 'Love Always, Petra'.
Two years later, she is also a staple of gossip magazines because of her romantic relationship with the 'You're Beautiful' singer James Blunt.
John Lewis is hoping the campaign will attract new shoppers into its fashion departments by raising awareness of the different brands it stocks.
Mark Forsyth, spokesperson for John Lewis, said: "Petra was great to work with, she's relaxed and genuinely enjoyed trying on the looks we created for out using a variety of the brands we stock including Joseph, Seven For All Mankind, Farhi, Coast, Principles and many others as well as our best-selling own brand JL."
The campaign is aimed at customers aged from their 20s to their 50s. It breaks on September 25.
Lowe London picked up the 拢13m John Lewis creative account in July, winning it from Burkitt DDB. The department store chain is now holding pitches for its media account.
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