Perhaps Cher's in bed, scratching bottom (4)
I believe the answer is:
diva
'perhaps cher's' is the definition.
(Cher might be considered a diva)
'bed scratching bottom' is the wordplay.
'bed' becomes 'divan' (type of bed).
'scratching bottom' means to remove the last letter.
'divan' with its last letter removed is 'DIVA'.
'in' is the link.
(Other definitions for diva that I've seen before include "High-maintenace woman" , "Operatic ego" , "Top opera singer" , "Prima dona" , "A female opera singer" .)