Ideal occasion to watch TV (5,4)
I believe the answer is:
prime time
'watch tv' is the definition.
The definition and answer can be both related to time as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'ideal occasion' is the wordplay.
'ideal' becomes 'prime' (I can't justify this - if you can you should believe this answer much more).
'occasion' becomes 'time' (I've seen this before).
'prime'+'time'='PRIME TIME'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for prime time that I've seen before include "When most TV is watched" , "For monks perhaps around dawn" , "Optimum period for broadcasters" , "Peak viewing period" , "when most view" .)