Performers twisting end of musical (4)
I believe the answer is:
cast
'performers' is the definition.
(I've seen this before)
'twisting end of musical' is the wordplay.
'twisting' becomes 'ca' (I am not sure about this - if you are sure you should believe this answer much more).
'end of' says to hollow out the word (remove centre letters) (I've seen 'ends of' mean this).
'musical' becomes 'Show Boat' (musical by Jerome Kern).
'showboat' with its middle removed is 'st'.
'ca'+'st'='CAST'
(Other definitions for cast that I've seen before include "Play's actors" , "Form < > company" , "Throw off; select (actor)" , "Team of actors in a play" , "'Ne'er .... a clout till May be out'" .)