Popular couple at work (2,7)
I believe the answer is:
in harness
'at work' is the definition.
(I've seen this in another clue)
'popular couple' is the wordplay.
'popular' becomes 'in' ('in' can mean trendy).
'couple' becomes 'harness' (I've seen this before).
'in'+'harness'='IN HARNESS'
(Other definitions for in harness that I've seen before include "Performing routine daily work" , "Working together" .)