Funny clip of Mr Benn is capturing your heart (9)
I believe the answer is:
hilarious
'funny' is the definition.
(thesaurus)
'clip of mr benn is capturing your heart' is the wordplay.
'clip of' means to remove the last letter (clip can mean a shortening of something).
'mr benn' becomes 'hilary' (politician Hilary Benn).
'capturing' is an insertion indicator.
'heart' indicates the central letters.
The middle of 'your' is 'ou'.
'hilary' with its last letter taken away is 'hilar'.
'is' enclosing 'ou' is 'ious'.
'hilar'+'ious'='HILARIOUS'
(Other definitions for hilarious that I've seen before include "A scream" , "Priceless!" , "Extremely funny" , "Uriah's oil (anag.)" , "Extremely amusing" .)