The Legend of Zelda: Skyward Sword includes a "key" musical instrument, similar to the ocarina in Ocarina of Time.
Nintendo composer Mahito Yokota revealed the feature in a new Iwata Asks interview with company boss Satoru Iwata.
The Zelda team have thus far kept schtum on the idea, despite multiple showings to press over the game's four-year development.
What will playing the under wraps instrument do? "It's still a secret," Yokota teased. "Keep your ears pricked though."
Skyward Sword isn't the first Zelda game to use music during gameplay. Apart from obvious example Ocarina of Time, seafaring GameCube title Wind Waker had players conducting songs with their titular baton. The original Legend of Zelda had a secret-revealing recorder, while Game Boy classic Link's Awakening tasked players with assembling an orchestra to awaken the mysterious Wind Fish.
Nintendo will finally launch Skyward Sword later "this year" - it's currently listed with a "holiday" release.