Crossword Genius

Immediately get on well (3,2,3)

Ross

I believe the answer is:

hit it off

(Other definitions for hit it off that I've seen before include "Become immediate friends" , "Develop a good friendly relationship" , "Become compatible and friendly" , "Be well suited" , "Get on well with - or knock from position?" .)

I've seen this clue in The Guardian.
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