Song from pub singer King famously (9)
I believe the answer is:
barcarole
'song' is the definition.
(barcarole is a kind of song)
'from pub singer king famously' is the wordplay.
I cannot really see how this works, but
'from' could be 'o' (I've seen this in other clues) and 'o' is found in the answer.
'pub' could be 'bar' (both are drinking establishments) and 'bar' is present in the answer.
'king' could be 'r' (abbreviation of Latin rex) and 'r' is present in the answer.
The remaining letters 'cale' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for barcarole that I've seen before include "music of Venice" , "Venetian boat song" , "Italian song" , "Gondolier's song" , "Venetian boating song" .)