Choose to eat before 'Cheers' that's staged in theatre (8)
I believe the answer is:
operetta
'theatre' is the definition.
(I know that operetta is a type of musical theater)
'choose to eat before cheers' is the wordplay.
'choose' becomes 'opt' (both can mean to pick something).
'to eat' is an insertion indicator.
'before' becomes 'ere' (poetic term).
'cheers' becomes 'ta' (both can mean thank you).
'opt' enclosing 'ere' is 'operet'.
'operet'+'ta'='OPERETTA'
'that's staged in' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for operetta that I've seen before include "work of note" , "Eg, Die Fledermaus" , "Light musical drama" , "piece of music?" , "some music theatre" .)