Eurovision winner with Boom Bang-a-Bang (4)

I believe the answer is:

lulu

(Other definitions for lulu that I've seen before include "Exceptional thing (colloq.); Berg opera" , "modern opera" , "Berg opera; outstanding thing (colloq.)" , "UK 14 7 [EURO VISION] entrant" , "Outstanding person or thing" .)

I've seen this clue in The Guardian.

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