Film star, fool taken in by fraud (6)
I believe the answer is:
lassie
'film star' is the definition.
(fictional dog in several films)
'fool taken in by fraud' is the wordplay.
'fool' becomes 'ass' (ass is a kind of fool).
'taken in by' indicates putting letters inside.
'fraud' becomes 'lie' ().
'ass' going inside 'lie' is 'LASSIE'.
(Other definitions for lassie that I've seen before include "Screen canine" , "girl found" , "Hollywood film-star dog" , "''Will ye go ..., go'' (folksong)" , "Scottish girl - canine movie star" .)