For the next seven weeks KFC and Pizza Hut customers around the world will be invited to add a small amount of money to their bill. In the UK this will be 5p in KFC and 20p in Pizza Hut. During the Hunger Relief Week KFC will match each 5p customer donation.
The two chains have 35,000 stores across the world, serving a total of 115m customers each week. The WFP feeds around 90m each year in more than 80 of the world's poorest countries.
Yum! is going for a wider audience by encouraging its 1m employees to organise their own fundraising initiatives and by also mounting a global ad campaign which will encourage people to fight the problem of hunger by donating money online.
Josette Sheeran, executive director of the WFP, said: "This campaign will raise awareness among tens of millions of people around the world."
Agencies working for Yum! on the campaign include Weber Shandwick handling international PR and DesignBridge handling UK point of sale material.