Singer's festive song getting longer (6,4)

I believe the answer is:

carole king

'singer's' is the definition.
(Carole King 1958- the American singer)

'festive song getting longer' is the wordplay.
'festive song' becomes 'carol'.
'getting longer' becomes 'eking' (eke can mean make last longer).
'carol'+'eking'='CAROLE KING'

I've seen this clue in The Everyman puzzle in The Observer.

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