Film star's tirade after end of screening (5)
I believe the answer is:
grant
'film star's' is the definition.
'tirade after end of screening' is the wordplay.
'tirade' becomes 'rant' (I've seen this before).
'after' is a charade indicator (letters next to each other).
'end of' suggests the final letters.
The last letter of 'screening' is 'g'.
'rant' put after 'g' is 'GRANT'.
(Other definitions for grant that I've seen before include "Allow (something)" , "Give (a right, property, etc)" , "cash received" , "Monetary aid" , "Confer" .)