... and here's another about a gangster's girlfriend somewhere in Belgium (4,8)
I believe the answer is:
moll flanders
'and here's another' is the definition.
I can't judge whether this defines the answer.
'a gangster's girlfriend somewhere in belgium' is the wordplay.
'a gangster's girlfriend' becomes 'moll' (I've seen this before).
'somewhere in belgium' becomes 'flanders' (I can't justify this - if you can you should believe this answer much more).
'moll'+'flanders'='MOLL FLANDERS'
'about' is the link.
Can you help me to learn more?
(Other definitions for moll flanders that I've seen before include "(Female) Defoe novel" , "titled woman" , "Adventuress" , "Book by Defoe" , "Defoe romance" .)