Celeb with one instrument (5)
I believe the answer is:
sitar
'instrument' is the definition.
(I know that sitar is a type of stringed instrument)
'celeb with one' is the wordplay.
'celeb' becomes 'star' (I've seen this before).
'with' indicates putting letters inside.
'one' becomes 'I' (Roman numeral).
'star' placed around 'i' is 'SITAR'.
(Other definitions for sitar that I've seen before include "Large Indian lute" , "music-maker" , "Guitar-like instrument" , "Hindu stringed instrument" , "Indian stringed instrument" .)