Performer on stage gets to behave badly (3,2)
I believe the answer is:
act up
'to behave badly' is the definition.
(act up can mean to misbehave)
'performer on stage' is the wordplay.
I cannot really understand how this works, but
'performer' could be 'act' (someone with an act) and 'act' is found in the answer.
The remaining letters 'up' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'gets' acts as a link.
Can you help me to learn more?
(Other definitions for act up that I've seen before include "Behave badly, give trouble" , "Misbehave - carry on" , "Give trouble, make a fuss" , "create fireworks display?" , "Behave like a brat" .)