A mess - it may be produced by artist (7)
I believe the answer is:
matisse
'artist' is the definition.
(Henri Matisse)
'a mess it may be' is the wordplay.
'may be' indicates anagramming the letters.
'a'+'mess'+'it'='amessit'
'amessit' is an anagram of 'MATISSE'.
'produced by' is the link.
(Other definitions for matisse that I've seen before include "20th century French painter" , "Henri ---, Fauvist painter" , "Henri -, Fr. artist" , "French painter, Henri, d.1954" , "Is mates turned on the French painter" .)