Dead strange lecturer becomes attached later (5,2)

'attached later' is the definition.
'added on' can be an answer for 'attached' (adding on is a kind of attaching). I'm unsure of the 'later' bit.

'dead strange lecturer' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'dead' is 'adde' which is located in the answer.
'lecturer' could be 'don' (I've seen this before) and 'don' is found within the answer.
No letters remain.
This may be the basis of clue (or it may be nonsense).

'becomes' acts as a link.

Can you help me to learn more?