The 4.5% abv cider will be packed in 50cl green bottles and appear from early May.
The launch will be backed by outdoor, press, online and TV advertising.
A sampling drive will aim to hit 100,000 consumers.
Supplier Beverage Brands is urging retailers to merchandise the product with cider rather than RTDs.
WKD Core is being aimed at extending usage among WKD drinkers, bringing lapsed WKD consumers back to the umbrella brand and recruiting new followers who like WKD’s irreverent ads but don’t drink RTDs.
Prices are expected to be comparable with Magners and Kopparberg.
Marketing director Debs Carter said: “We believe there is still room for expansion [in cider] by taking a different approach.
“Research has sown that there is demand among cider consumers for a sweeter, lighter cider with a more modern image.”