Musical drama extremely twee work (7)
I believe the answer is:
'work' is the definition.
'musical drama extremely twee' is the wordplay.
'musical drama' becomes 'opera' (I've seen this in another clue).
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'twee' with its middle removed is 'te'.
(Other definitions for operate that I've seen before include "(Of machine) function" , "Carry on business" , "Function; run" , "Make to work" , "Work as a surgeon" .)