"Knowing Me, Knowing You” group (4)
I believe the answer is:
abba
'knowing me knowing you group' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for abba that I've seen before include "striped coat?" , "Old group" , "group of four stars?" , "Scandinavian supergroup" , "1970s Swedish pop group" .)