Two boys, one hosting uni event, one on stage (9)
I believe the answer is:
tragedian
'one on stage' is the definition.
(actor who performs tragedy)
'two boys one hosting uni event' is the wordplay.
'two boys' can mean two substitutions for 'boy'.
'boy' becomes 'Ted' (short for Edward or Theodore).
'boy' becomes 'ian' (man's name).
'one hosting' means one lot of letters goes inside another (inserted letters are welcomed in or hosted).
'uni event' becomes 'rag' (type of charity event at some universities).
'ted'+'ian'='tedian'
'tedian' placed around 'rag' is 'TRAGEDIAN'.
(Other definitions for tragedian that I've seen before include "Egad, I rant about actor in sad drama" , "actor in Macbeth?" , "Egad, I rant about dramatic actor" , "A great din (anag) - actor" , "Dramatist" .)