Turn creative — work on Picasso, primarily (5,5)
I believe the answer is:
party piece
'turn' is the definition.
(both can mean a performance)
'creative work on picasso primarily' is the wordplay.
'creative' becomes 'arty' (I've seen this before).
'work' becomes 'piece' (I have seen 'Musical work' mean 'piece' so perhaps 'work' could also mean 'piece').
'on' is a charade indicator (letters next to each other).
'primarily' says to take the initial letters.
The initial letter of 'picasso' is 'p'.
'arty'+'piece'='artypiece'
'artypiece' put after 'p' is 'PARTY PIECE'.
(Other definitions for party piece that I've seen before include "Individual act to entertain socially" , "Act with which to entertain friends" , "Amusing performance done to entertain others informally" .)