London theatre players itch occasionally (5)
I believe the answer is:
lyric
'london theatre' is the definition.
(the Lyric is a West End theatre)
'players itch occasionally' is the wordplay.
'occasionally' means one should take alternating letters (letters taken at regular intervals or occasions).
'players'+'itch'='playersitch'
The alternate letters of 'playersitch' are 'LYRIC'.
(Other definitions for lyric that I've seen before include "having a light quality" , "Expressing the poet's emotions" , "Airline" , "something to sing about? On the contrary" , "Song's words" .)