The free app provides the latest news and reviews from the world of fashion, celebrity and beauty, in an easy-to-navigate environment.
As part of eBay Fashion's three-month sponsorship, the online retailer has bespoke in-app branding and video, along with ownership of all advertising, which clicks through to the eBay fashion store.
Mike Newcombe, director of mobile advertising at IPC, said: "The Marie Claire mobile app will keep fashion fans up to date and in the know, all within a premium, made-for-mobile environment.
"For eBay Fashion, the app delivers the ideal audience, who, within a matter of clicks, can move seamlessly from inspiration through to eBay's checkout."
Sham Islam, strategic lead at eBay's digital agency Essence, said: "We feel that this is the perfect environment to showcase the steps forward that have been made in terms of eBay's fashion offering.
"The brand presence is strong without being intrusive and we are pleased to be the launch partner of an app that we know the eBay fashion audience will love."
The launch of Marie Claire's smartphone app adds to the brand's existing digital offering, which includes a mobile optimised website, a Beauty Genius iPhone app, and a Marie Claire Runway iPad app.
EBay recently recruited Andrea Linett as creative director as part of the company's overall push in the clothing sector.
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