Heinz is to sell an initial 3,000 bottles of its latest tomato ketchup exclusively on Facebook in an experiment combining grocery sales with the social networking site.
UK consumers will be able to buy the limited edition run of Heinz tomato ketchup with balsamic vinegar -- the first variation on the original --through the Heinz UK page on Facebook.
Customers will have to "like" the page to buy a bottle, potentially sharing news of their purchase with the average 130 friends of each Facebook user.
The rest of the 1,000,057 bottles will be on supermarket shelves from the middle of this month.
The new flavour swaps the traditional spirit vinegar for balsamic vinegar.
Heinz marketing manager Ian McCarthy said: "As a leading grocery company Heinz is very much aware of the evolving channels consumers use to buy and engage with brands.
"Social media is increasingly at the forefront of this consumer consumption evolution which is why we've decided to use our popular UK Facebook page to ensure our most loyal fans get the chance to try Heinz tomato ketchup with balsamic vinegar before anyone else.
"We are anticipating demand will be high and the product will sell out in days," Mr McCarthy added.
Online grocer Ocado said it was watching "with interest", but pointed out people could buy multiple foods in one transaction on its website, whereas Heinz was only selling one product.
A spokesman said: "We'll be very keen to see how it goes. The online retail space is growing very quickly and there's room for everyone."
Heinz sells more than 76 million bottles of ketchup each year in the UK alone and around 650 million bottles and 11 billion sachets across six continents, according to figures.