Girl getting up after six in capital city (6)
I believe the answer is:
vienna
'capital city' is the definition.
(capital of Austria)
'girl getting up after six' is the wordplay.
'girl' becomes 'anne' (girl's name).
'getting up' says the letters should be written backwards.
'after' means one lot of letters go next to another.
'six' becomes 'VI' (Roman numerals).
'anne' backwards is 'enna'.
'enna' put after 'vi' is 'VIENNA'.
'in' acts as a link.
(Other definitions for vienna that I've seen before include "Adult home of Beethoven, Brahms, Mozart and Schubert" , "On the Danube, it was home to many great composers" , "Austrian city of the waltz" , "somewhere in Austria" , "City of Strauss and the waltz" .)