Quite unexpectedly (3,2,3,4)

I think it could be either:

out of the blue

all of asu dden

'quite unexpectedly' is the definition.
(I've seen this before)

This is the entire clue.

(Other definitions for out of the blue that I've seen before include "Suddenly" , "From nowhere" , "Quite unexpectedly" , "Entirely unexpectedly" , "Without warning" .)

I've seen this clue in The Guardian.

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