Indian instrument, one held by celebrity (5)
I believe the answer is:
sitar
'indian instrument' is the definition.
(I've seen this before)
'one held by celebrity' is the wordplay.
'one' becomes 'i' (Roman numeral).
'held by' means one lot of letters goes inside another.
'celebrity' becomes 'star' (I've seen this before).
'i' put within 'star' is 'SITAR'.
(Other definitions for sitar that I've seen before include "It takes pluck" , "Long-necked musical instrument of India" , "Indian musical instrument like long-necked lute" , "Astir with Indian long-necked lute" , "music-maker" .)