Puritan it's said is featured in film (8)
I believe the answer is:
moralist
'puritan' is the definition.
(both can mean a sanctimonious person)
'said is featured in film' is the wordplay.
'said' becomes 'oral' (both can mean spoken).
'is featured in' is an insertion indicator.
'film' becomes 'mist' (to film over is to mist or fog over).
'oral' going inside 'mist' is 'MORALIST'.
'it's' acts as a link.
(Other definitions for moralist that I've seen before include "Ethical figure" , "Disciplinarian" , "Good teacher" , "preacher" , "Ail storm (anag)" .)