Popular couple split up (2,3)
I believe the answer is:
in two
'split up' is the definition.
'in two' can be an answer for 'split' (I've seen this in another clue). I'm not sure about the 'up' bit.
'popular couple' is the wordplay.
'popular' becomes 'in' (something that's 'in' is fashionable).
'couple' becomes 'two' (two people or things).
'in'+'two'='IN TWO'
Can you help me to learn more?
(Other definitions for in two that I've seen before include "Asunder" , "divided up thus?" , "Completely divided" , "simply split" , "apart" .)