Music, say, rubbish? I'm not sure, for jazz pianist (3,5)

I believe the answer is:

art tatum

'for jazz pianist' is the definition.
(US pianist Art Tatum, 1909-1956)

'music say rubbish? i'm not sure' is the wordplay.
'music say' becomes 'art' (music is a kind of art).
'rubbish?' becomes 'tat' (low-quality items or material).
'i'm not sure' becomes 'um' (expression of hesitation).
'art'+'tat'+'um'='ART TATUM'

I've seen this clue in The Guardian.

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