Ben is turning into a dramatist (5)
I believe the answer is:
ibsen
'a dramatist' is the definition.
(I know this)
'ben is turning' is the wordplay.
'turning' is an anagram indicator.
'ben'+'is'='benis'
'benis' is an anagram of 'IBSEN'.
'into' acts as a link.
(Other definitions for ibsen that I've seen before include "Norwegian playwright (Peer Gynt)" , "Noted Norwegian playwright" , "'Ghosts' writer" , "not one for 'All work and no play ...'" , ""Doll's House" dramatist" .)