Avid sort of performer (4)
I believe the answer is:
diva
'performer' is the definition.
(diva is a kind of performer)
'avid sort' is the wordplay.
'sort' is an anagram indicator.
'avid' with letters rearranged gives 'DIVA'.
'of' is the link.
(Other definitions for diva that I've seen before include "Callas, say" , "One who sings" , "Celebrated female operatic star" , "For example Sutherland" , "Prima dona" .)