Created by McCann Erickson London, the campaign puts social media at its heart by asking members of the public to upload a picture and profile of their nana or someone they know to a specially created Facebook Fan page.
Consumers will then be given the chance to vote for their favourite Nana, with the winner appearing on Shreddies packaging later in the year.
The social media work will be supported by an on-pack promotion, as well a 10-second TV ad, which will go live on 26 April.
The spot, called "The New Face of Shreddies", will be tagged on to the end of the current Shreddies TV ad, which sees the current Shreddies Nanas having a makeover.
Craig Turner, the senior brand manager for Shreddies, said: "This activity truly engages with our consumers, providing a very personal interaction as they upload and vote for their favourite nana."