UPDATE 8/10/14 11.55am: The Wii U GameCube controller adapter will only be compatible with Super Smash Bros., Nintendo has now said.
The company has changed the listing on the accessory's official product page and apologised for the mix-up.
"The GameCube Controller Adapter for Wii U is compatible with Wii U and Super Smash Bros. for Wii U specifically - it is not compatible with any other Wii U software," a Nintendo UK spokesperson has told Eurogamer.
"The adapter is also not compatible with Wii and we apologise for any confusion."
Initially, the adapter's listing stated that it would be compatible with all games that utilised the Wii Classic Controller and Classic Pro Controller, as well as the Wii U Pro Controller. Both of these statements have now been removed.
ORIGINAL STORY 8/10/14 9.10am: Nintendo's upcoming Wii U GameCube controller adapter will make the classic pad compatible with a range of games - not just Super Smash Bros.
A new product description for the accessory states that it will allow you to use a GameCube controller with any title that supports the Wii U Pro Controller.
That means you can use a GameCube pad to control Mario Kart 8, New Super Mario Bros. U, Pikmin 3, Super Mario 3D World, Zelda: Wind Waker HD, Bayonetta 2 and Donkey Kong Country: Tropical Freeze, amongst many others.
"This adapter will allow you to connect your GameCube controller to the Nintendo Wii U," the product description on Nintendo UK's site reads.
"Connect your GameCube controller to your Wii U console. Compatible with all games supported by the Wii U Pro Controller."
Priced at Ł17.99, the adapter can connect with four GameCube pads (including Wavebirds) and is due to be released alongside Super Smash Bros. for Wii U on 5th December. A new Smash-branded GameCube pad will be available to buy on that date too.
An earlier version of the listing mentioned that the adapter would also support games controlled by the Wii Classic Controller and Wii Classic Controller Pro - but all mention of these has now been removed.