The treat, which is made by Cadbury, will be reduced from 26p to 10p from today (Jan 21) in Tesco stores.
It follows repeated requests from customers for the product to return to its former price, even after Cadbury reduced the cost from 30p to 25p in March of last year.
Labour leader Jeremy Corbyn has criticised the rising price of the chocolate bar, saying it needed to be looked into.
“I think we need to examine this question in some detail and see if there is excessive profit-making by those who make Freddos - then they’ve got us to answer to,” he said in an interview with digital football platform Copa90 in February 2018.
Tesco’s special deal is part of a wider range of celebratory price drops which the supermarket has launched to mark its centenary year.
Chief customer officer, Alessandra Bellini, said: “We understand that the nation wanted to see the price of the iconic Freddo chocolate bars return to the original price of 10p.
“Given we are celebrating 100 years of great value, we’re really pleased to have been able to give our customers what they want, and have some fun at the same time!”