Musicians play them for Prunella (6)
I believe the answer is:
scales
This clue is a double definition.
'musicians play them' is the first definition.
'prunella' is the second definition.
(Prunella Scales British actress)
'for' is the link.
(Other definitions for scales that I've seen before include "Instruments for weighing things" , "Set of musical notes - balanced on a fish?" , "Measuring instrument for weighing" , "a number of small plates" , "Fish flake or weighing device" .)