TV programme in which dog devours headgear (4,4)
I believe the answer is:
chat show
'tv programme' is the definition.
(I've seen this before)
'dog devours headgear' is the wordplay.
'dog' becomes 'chow' (short for chow chow).
'devours' means one lot of letters goes inside another (I've seen this in other clues).
'headgear' becomes 'hats' (I've seen this in another clue).
'chow' going around 'hats' is 'CHAT SHOW'.
'in which' acts as a link.
(Other definitions for chat show that I've seen before include "TV programme genre" , "TV entertainment programme" , "TV discussion programme" , "Programme on which celebs talk" , "Airing of gas" .)