The UK's biggest retailer invited reporters to join chief executive Dave Lewis at its site in Chatteris, Cambridgeshire, on Wednesday.
The new chain is named after Jack Cohen, who founded Tesco 99 years ago, earning the nickname "Slasher Jack" for his "pile-it-high, sell-it-cheap" approach to retailing.
Tesco plans to open another 15 branches over the next year, five of which will be converted from existing Tesco stores.
Workers unveil the branding at Tesco's new discount supermarket Jack's, in Chatteris, Britain, September 19, 2018.
In addition to the Jack's brand, Jack's will stock some familiar grocery brands and a range of general merchandise on a "When it's Gone, It's Gone" basis, Tesco said.
'It's fitting that today, we mark the beginning of Tesco's celebration of 100 Years of Great Value by launching a new brand, and stores bearing his name: Jack's'. Their growth continues to far outpace traditional supermarkets.
Although Tesco is Britain's biggest chain with a 27.4 percent share, according to the latest industry data, it could be overtaken by Sainsbury's proposed 7.3 billion pound ($9.6 billion) takeover of Asda.
According to Kantar Worldpanel, Lidl and Aldi are the fastest growing retailers in the United Kingdom now.
In a statement the company simply said it would be "sharing some exciting news" after earlier advertisements for staff for a "new store format" in Chatteris.