First screening about to follow Empire broadcast (8)
I believe the answer is:
premiere
'first screening' is the definition.
(I've seen this before)
'about to follow empire broadcast' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'to follow' means one lot of letters go next to another (some letters go after or follow others).
'broadcast' indicates an anagram (letters scattered or cast around).
'empire' is an anagram of 'premie'.
're' put after 'premie' is 'PREMIERE'.
(Other definitions for premiere that I've seen before include "Play's first public performance" , "Opening night" , "significant performance" , "Opening performance" , "First showing of play or film" .)