入戏太深演得逼真
[rù xì tài shēn yăn dé bī zhēn]
'Ru Xi Tai Shen Yan De Bi Zhen' literally means 'Playing a role too deeply results in realistic performance'. This implies being deeply lost into some emotion or state to the point of becoming extremely convincing or true to form. People sometimes get themselves involved so deeply within that emotion and forget themselves.