First on stage, not turning to don cloak and topper (8)
I believe the answer is:
capstone
'topper' is the definition.
(stone which goes on top of a building)
'first on stage not turning to don cloak' is the wordplay.
'first on stage' becomes 's' (I can't justify this - if you can you should believe this answer much more).
'turning' is an anagram indicator.
'to don' is an insertion indicator (don can mean to wear).
'cloak' becomes 'cape' (cape is a kind of cloak).
'not' is an anagram of 'ton'.
's'+'ton'='ston'
'ston' put inside 'cape' is 'CAPSTONE'.
'and' is the link.
(Other definitions for capstone that I've seen before include "Part of coping" , "What's put on wall" , "Piece on top of wall, etc" .)