Chrissie Hynde has led a boycott of London department store Fortnum & Mason for selling foie gras sourced from pipe-feeding birds.
Her support comes as Peta (People for the Ethical Treatment of Animals) awards Fortnum & Mason the Cruellest Retailer accolade for its trade in foie gras.
The charity has organised for supporters to visit the famous store to present the company's officials with the award.
Peta says Fortnum & Mason has risen "to the height of hypocrisy" for holding its Food and Drink Awards for British talent while profiting from foie gras sales - production of which is illegal in the UK.
Foie gras is made by pipe-feeding birds huge amounts of grain and fat so their livers become diseased and swell. Often the pipe used to force-feed the animals puncture their throats, leading them to bleed to death.
Mimi Bekhechi, associate director of Peta, said: "Selling foie gras and profiting from the violent abuse of birds is about as British as the Eiffel Tower.
"People who think that they are showing their taste for haute cuisine by consuming foie gras should know that what they're actually eating is the diseased livers of tortured animals."
In support of Peta's boycott of Fortnum & Mason, the lead singer of The Pretenders appealed to Fortnum & Mason managing director Ewan Venters to stop selling foie gras in an open-letter.
Hynde's support followed a film released following a Peta investigation, which showed the conditions at a farm represented by the Sarlat Perigord cooperative, from which Fortnum & Mason's distributor sources foie gras.
She said: "I watched footage of foie gras farms, the very farms which supply your distributor, and I saw these birds have pipes shoved down their throats several times a day in order to force grain, maize and fat into their stomachs.
"And for what? So that their swollen livers can be sold to the small minority of people who still think it's acceptable to abuse animals for a fleeting flavour?
"I'll stand by you, Mr Venters, just as soon as you stop the sale of foie gras in your store. Until then, I'll be avoiding Fortnum's like the plague and will be encouraging my friends and family to do the same."
Fortnum & Mason denied the footage was taken at a farm that supplied their foie gras and defended their sale of the product: "Fortnum & Mason is a traditional retailer who over the centuries has established a strong reputation for supplying certain traditional foods, amongst which is foie gras.
"As a retailer we are here to provide our customers with the products they ask for, including foie gras and we respect their right to buy and enjoy the foods they like."