Excited by a bet on the gee-gees (8)
I believe the answer is:
aflutter
'excited' is the definition.
(similar in meaning)
'a bet on the gee-gees' is the wordplay.
'a bet' becomes 'flutter' (to have a flutter is to put a bet on).
'on' is a charade indicator (letters next to each other).
'the gee gees' becomes 'a' (I can't explain this - if you can you should believe this answer much more).
'flutter' put after 'a' is 'AFLUTTER'.
'by' is the link.
Can you help me to learn more?
(Other definitions for aflutter that I've seen before include "trembling" , "in excited state" , "Agitated - excited (eg in anticipation)" , "Nervous, twitchy" , "is rather nervous" .)