Singer’s accountant plugging very old record (8)
I believe the answer is:
vocalist
'singer's' is the definition.
(synonyms)
'accountant plugging very old record' is the wordplay.
'accountant' becomes 'CA' (abbreviation for chartered accountant).
'plugging' indicates putting letters inside (inserted letters plug up a gap in the word).
'very' becomes 'v' (abbreviation).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'record' becomes 'list' (list is a type of record).
'v'+'o'+'list'='volist'
'ca' going into 'volist' is 'VOCALIST'.
(Another definition for vocalist that I've seen is " Singer with a pop group".)