The grocer claims the ‘Social Price Drop’ promotion is the first time a supermarket has determined the price of a product through crowdsourcing.
Lidl will invite the public to cut the cost of a different festive product each week in the four weeks leading up to Christmas.
The first phase launches today (21 November) and the grocer’s Christmas lobster, which usually retails at £5.99, will be the first product to have its price set through the strength of conversation on Twitter.
Customers have two days to drive down the price of the lobster by tweeting about it and on Wednesday the final product price will be announced and the product will be available for sale from Saturday.
A special reduced price tag will highlight the socially driven price cut in-store. Lidl will repeat the process with three other flagship products in the weeks before Christmas.
Activity is designed to highlight Lidl’s commitment to providing shoppers with products at "incredible" value.
A Lidl spokeswoman said: "Today’s launch of the Social Price Drop is a first for any supermarket in the UK.
"Christmas is a very expensive time of year for shoppers up and down the country, and as a retailer at the heart of Britain’s communities, our ambition is to put the control back into the hands of consumers, and save them even more in the run up to Christmas."
The social media campaign is supporting the Lidl’s Christmas ad campaign, which seeks to illustrate the brand’s authenticity, provenance and quality alongside its value credentials.
The strategy and creative was handled by 360i Europe.