Perform musical drama before empty theatre (7)
I believe the answer is:
operate
'perform' is the definition.
(thesaurus)
'musical drama before empty theatre' is the wordplay.
'musical drama' becomes 'opera' (I've seen this before).
'before' is a charade indicator (letters next to each other).
'empty' suggests removing the centre.
'theatre' with its middle taken out is 'te'.
'opera'+'te'='OPERATE'
(Other definitions for operate that I've seen before include "Make function" , "Work, run" , "Manage, run" , "Function; run" , "Perform as surgeon does" .)