Guitarist, American celebrity, turned up after ten (6)
I believe the answer is:
axeman
'guitarist' is the definition.
(axeman can informally mean a guitarist)
'american celebrity turned up after ten' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'celebrity' becomes 'name' (as in a 'big name').
'turned up' shows that the letters should be reversed in order.
'after' is a charade indicator (letters next to each other).
'ten' becomes 'X' (Roman numeral).
'name' reversed gives 'eman'.
'eman' put after 'x' is 'xeman'.
'a'+'xeman'='AXEMAN'
(Other definitions for axeman that I've seen before include "One making cuts in expenditure" , "Ruthless cutter of costs (informal)" , "Killer" , "Guitarist (slang)" , "who may give others the chop!" .)