I appreciate the cameo line before Hamlet enters (3,4,6,4,6)

'hamlet enters' is the definition.
I know nothing about this answer so I can't judge whether this works.

'i appreciate the cameo line' is the wordplay.
I cannot really understand how this works, but
'i' could be 'a' and 'a' is present in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
'line' could be 'el' (el is a kind of line) and 'el' is found in the answer.
This may be the basis of the clue (or it may be nonsense).

'before' acts as a link.

Can you help me to learn more?