British artist’s underwear (3)
I believe the answer is:
bra
'underwear' is the definition.
(I've seen this before)
'british artist's' is the wordplay.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'b'+'ra'='BRA'
(Other definitions for bra that I've seen before include "support" , "one carrying chest" , "Underwear item" , "Female undergarment" , "Chest supporter" .)