Composer adds note to performance (5)
I believe the answer is:
greig
'composer adds note to performance' is the definition.
I know that 'note' relates to this answer.
'note to performance' is the wordplay.
I cannot quite understand how this works, but
'note' could be 're' (as in do-re-mi) and 're' is present in the answer.
'performance' could be 'gig' (a gig is a musical concert) and 'gig' is found in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for greig that I've seen is " Former England cricket captain".)