Provide backing following black musician (7)
I believe the answer is:
bassist
'musician' is the definition.
(bass guitarist)
'provide backing following black' is the wordplay.
'provide backing' becomes 'assist' (to assist is to back or support).
'following' says to put letters next to each other.
'black' becomes 'b' (as in pencil classifications).
'assist' after 'b' is 'BASSIST'.
(Other definitions for bassist that I've seen before include "Musician" , "jazz player" .)