Rock star's undercover operation (5)
I believe the answer is:
sting
I believe this clue is a double definition.
'rock star's' is the first definition.
(I've seen this in another clue)
'undercover operation' is the second definition.
(I've seen this in another clue)
(Other definitions for sting that I've seen before include "Bee/wasp wound" , "Wound from wasp" , "Smart - cheat" , "The pain caused by bee or nettle" , "18, sharp pain" .)