Fictional collie (6)
I believe the answer is:
lassie
'fictional collie' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for lassie that I've seen before include "Hollywood film-star dog" , "Screen canine" , "Canine film star" , "Film and TV dog" , "Scots girl - film dog" .)