Cares about couple being popular? Switched to being undecided (2,3,5)
I believe the answer is:
in two minds
'being undecided' is the definition.
(I've seen this before)
'cares about couple being popular? switched' is the wordplay.
I cannot really see how this works, but
'cares' could be 'minds' (I've seen this in another clue) and 'minds' is found within the answer.
'couple' could be 'two' (a couple can mean two of something) and 'two' is located in the answer.
'popular?' could be 'in' ('in' can mean trendy) and 'in' is located in the answer.
No letters remain.
This explanation may well be incorrect...
'to' acts as a link.
Can you help me to learn more?
(Other definitions for in two minds that I've seen before include "like Dr Jekyll at times?" , "Torn" , "where similar ideas may be foolish or clever" , "Wavering, undecided" , "The outcome is uncertain" .)