Actor performs, but not with a metal band (4)
I believe the answer is:
torc
'band' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for torc that I've seen before include "Choker" , "Celtic metal neck-ring" , "Metallic neck ornament" , "Rigid circular necklace" , "Twisted metal neck band" .)