Collie of TV (6)
I believe the answer is:
lassie
'collie of tv' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for lassie that I've seen before include "Hollywood film-star dog" , "dog in pictures" , "TV series/film dog" , "Young Scottish girl or Hollywood lost dog" , "Screen mutt - Scottish girl" .)