He's excited about Gold on television showing trailer (8)
I believe the answer is:
horsebox
'trailer' is the definition.
(I've seen this before)
'he's excited about gold on television' is the wordplay.
'excited' indicates anagramming the letters.
'about' means one lot of letters goes inside another.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'on' means one lot of letters go next to another.
'television' becomes 'box' ('the box' can informally mean a television).
'hes' anagrammed gives 'hse'.
'hse' placed around 'or' is 'horse'.
'horse'+'box'='HORSEBOX'
'showing' is the link.
(Other definitions for horsebox that I've seen before include "Equine conveyance" , "Animal transporter" , "Equine transporter" , "It takes animals to the races" , "road trailer" .)