Its choir could be famous (8)
I believe the answer is:
historic
'famous' is the definition.
(I've seen this before)
'its choir could be' is the wordplay.
'could be' is an anagram indicator.
'its'+'choir'='itschoir'
'itschoir' anagrammed gives 'HISTORIC'.
(Other definitions for historic that I've seen before include "Momentous, noteworthy" , "sort of present" , "Choir sit (anag.)" , "Pertaining to what is important in the past" , "remarkable" .)