Piece of music, the last from Jocelyn Brown (6)
I believe the answer is:
number
'piece of music' is the definition.
(I've seen this before)
'last from jocelyn brown' is the wordplay.
'last from' says to take the final letters.
'brown' becomes 'umber' (umber is a kind of brown).
The last letter of 'jocelyn' is 'n'.
'n'+'umber'='NUMBER'
'the' is the link.
(Other definitions for number that I've seen before include "Part of musical" , "27, say" , "Is it sung" , "42, say" , "Mathematical value" .)