Celebrity goes outside club after one drink (8)
I believe the answer is:
libation
'drink' is the definition.
(libation is a kind of drink)
'celebrity goes outside club after one' is the wordplay.
'celebrity' becomes 'lion' (lion is a kind of celebrity).
'goes outside' indicates putting letters inside.
'club' becomes 'bat' (bat is a kind of club).
'after' is a charade indicator (letters next to each other).
'one' becomes 'i' (Roman numeral).
'bat'+'i'='bati'
'lion' going around 'bati' is 'LIBATION'.
(Other definitions for libation that I've seen before include "offering of wine" , "Drink poured as offering to the gods" , "Drink-offering" , "Ritual of pouring wine as sacrifice to a god" , "Drink poured out as offering to God" .)