Brilliant at music, strange being on tour of Australia (9)

'brilliant' is the definition.
Although both the answer and definition are adjectives, I cannot understand how they can define each other.

'music strange being on tour of australia' is the wordplay.
'music' becomes 'a'.
'strange being' becomes 'martin' (I can't justify this - if you can you should give a lot more credence to this answer).
'on' indicates putting letters inside (as in clothing 'on' a person).
'tour of' is an insertion indicator.
'australia' becomes 'oz' (informal name for Australia).
'a' placed inside 'martin' is 'martian'.
'martian' going around 'oz' is 'MOZARTIAN'.

'at' acts as a link.

Can you help me to learn more?