METADRAMA

The term metadrama is used when a play draws the attention of the audience to the fact it is a drama and a fiction. It occurs when the Chorus in Henry V refers to "this wooden O" or, more loosely, when Hamlet says: "The play's the thing/Wherein I'll catch the conscience of the king" meaning the Mouse-trap but reminding us that we are, at that moment, watching a play.
The device is sophisticated as it does counteract the "willing suspension of disbelief" normally required of an audience but it distances us for a while so that we may return in our emotions more intensely afterwards.
See more on this on Hamlet pages of: Classics of English Literature:essays by Barbara Daniels