Broadcast lecture to demonstrate it (4,4)
I believe the answer is:
talk show
'broadcast' is the definition.
(I know that talk show is a type of television program)
'lecture to demonstrate it' is the wordplay.
I cannot quite understand how this works, but
'lecture' could be 'talk' (synonyms) and 'talk' is present in the answer.
'demonstrate' could be 'show' (synonyms) and 'show' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for talk show that I've seen is " TV programme".)