Friend coming round is first to see painter (7)
I believe the answer is:
matisse
'painter' is the definition.
(I've seen this before)
'friend coming round is first to see' is the wordplay.
'friend' becomes 'mate' (mate is a kind of friend).
'coming round' indicates putting letters inside.
'first to' says to take the initial letters.
The initial letter of 'see' is 's'.
'is'+'s'='iss'
'mate' enclosing 'iss' is 'MATISSE'.
(Other definitions for matisse that I've seen before include "Henri -, C twenty Fr. painter, sculptor, illustrator" , "Henri ---, Fauvist painter" , "French painter, Henri, d.1954" , "French impressionist" , "20th century French painter" .)