Composer from Belgium enthralled by nude queen (6)
I believe the answer is:
barber
'composer' is the definition.
(Samuel Barber)
'belgium enthralled by nude queen' is the wordplay.
'belgium' becomes 'B' (abbreviation for Belgium).
'enthralled by' is an insertion indicator ('enthral' can mean 'capture').
'nude' becomes 'bare' (synonyms).
'queen' becomes 'r' (abbreviation for regina, e.g. in ER ).
'b' placed into 'bare' is 'barbe'.
'barbe'+'r'='BARBER'
'from' acts as a link.
(Other definitions for barber that I've seen before include "American composer; hairdresser" , "Sweeney Todd's occupation in Fleet Street" , "Sweeney Todd's profession in Fleet Street" , "Men's haircutter, musically of Seville?" , "Hair stylist" .)