Vangelis's No 1 single covered by pop artist (5)
I believe the answer is:
david
'artist' is the definition.
(French painter Jacques-Louis David)
'vangelis's no 1 single covered by pop' is the wordplay.
'vangelis's no 1' becomes 'v' (1st letter of 'vangelis').
'single' becomes 'I' (one).
'covered by' means one lot of letters goes inside another.
'pop' becomes 'dad' (both can mean one's father).
'v'+'i'='vi'
'vi' inserted inside 'dad' is 'DAVID'.
(Other definitions for david that I've seen before include "Dickens hero" , "Michelangelo statue" , "King of Judah and Israel, Saul's successor" , "singer/harpist?" , "Welsh saint - French painter" .)