The company is shortly to start selling triple-cooked chips that customers just pop in the oven. At £3 a serving, they'll be available from April 12.
The chips form part of a new chippie-inspired range that, says Metro, will also include beer battered cod or haddock and scraps, cider battered plaice, cider battered plaice fingers, scampi and whitebait.
They come courtesy of a deal with frozen food firm Fullers that will see the introduction of nine new frozen potato lines and three lines of chilled side dishes.
"With increasing focus on convenience and consumers buying into the benefits of frozen food, this is the perfect time for us to be joining forces with Marks & Spencer and strengthen stability within this market," says joint chief executive Jason Fuller.
And Carrie Joslin, M&S trading manager comments: "M&S is known for its food innovation and the four new products Fullers are creating for us are perfect examples of us listening to what newness customers want and making sure we deliver."
Marks & Spencer has to do something to stay ahead of the pack. With budget retailers such as Aldi and Lidl selling the likes of salmon, caviar and champagne, it's not easy to keep that luxury tag.
The company recently announced that it was launching packs of double-yolked eggs, and its Christmas range included such extravagances as gin infused with tea and speckled with gold flakes, a Christmas cake trimmed with LED lights and a chocolate cake decorated with five gold rings.
And the strategy seems to be working. Last November, while the company reported a fall in clothing sales - for the 13th quarter in a row - food sales rose by 1%, which was actually better than the market as a whole.
If you can't afford the price tag for M&S's triple-cooked chips, it's far cheaper - though a bit fiddly - to make them yourself. There's a recipe from the acknowledged master, Heston Blumenthal, here. Be warned, though, it requires a freezer as well as a deep-fat fryer, and takes over two and a half hours.