'The Great Alone', not getting on with parts by leading lady (9)
I believe the answer is:
alexander
'the great alone not' is the definition.
I can't judge whether this defines the answer.
'on with parts by leading lady' is the wordplay.
'on' is a charade indicator (letters next to each other).
'with' becomes 'and' (I've seen this before).
'parts by' becomes 'alex' (I can't justify this - if you can you should give a lot more credence to this answer).
'leading lady' becomes 'er' (Elizabeth Regina).
'and' after 'alex' is 'alexand'.
'alexand'+'er'='ALEXANDER'
'getting' is the link.
Can you help me to learn more?
(Other definitions for alexander that I've seen before include "A Great king of old Macedon" , "A great Greek ruler?" , "The Great Man" , "Macedon's "great" king, d. 323 BC" , "Great Greek military commander" .)