Nvidia is bundling The Witcher 3 and Batman: Arkham Knight with its GeForce GTX 980 and GTX 970 graphics cards.
That means if you buy either the GTX 980 and GTX 970 you get both CD Projekt's open-world RPG and Rocksteady's action adventure free.
It's a decent saving, but it's worth remembering both GPUs will set you back a fair few quid. The GTX 970 goes for between £250 and £295, and the 980 costs between £430 and £480.
Expanding on the deal (thanks CatmanBegins), if you buy a GeForce GTX 960, 970, 980, or 970M or above notebook, you get The Witcher 3 free.