Despite previous information that the GameCube Adapter, which allows GameCube controllers to be used for upcoming title Super Smash Bros. for Wii U, would be compatible with other Wii and Wii U titles in place of Wii Classic and Wii U Pro Controllers, Nintendo has clarified the situation.
The truth is that the GameCube Adapter will only work with Super Smash Bros. for Wii U, and that information detailing its compatibility with other Wii and Wii U software was a mistake.
Nintendo gave a statement to GameSpot:
"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. The adapter is also not compatible with Wii and we apologise for any confusion"The GameCube Adapter will release on 5th December in Europe, and 21st November in North America, alongside the fighter's launch, allowing up to four GameCube controllers to connect to the system and play the game.