Work in the theatre, perhaps (7)
I believe the answer is:
operate
'work' is the definition.
(I know that work can be written as operate)
'theatre perhaps' is the wordplay.
'theatre' becomes 'opera' (opera is a kind of theatre).
'perhaps' becomes 'te' (I can't justify this - if you can you should give a lot more credence to this answer).
'opera'+'te'='OPERATE'
'in the' acts as a link.
Can you help me to learn more?
(Other definitions for operate that I've seen before include "effect" , "Carry out surgery" , "Perform surgery or run a machine" , "Cause to function" , "(Of machine) function" .)