Traditional
曲艺 (folk performance art): one performer (the 'face') sits in front and mimes; another (the 'voice') hides behind and speaks/sings, so it looks like the front one is doing it all. Said to have been invented in the late Qing by the singer
黄辅臣 (Huáng Fǔchén) when his voice failed and his son spoke for him from behind a chair (per 《
新华词典》).