Work as a lookalike, say? (4,1,6,4)

'a lookalike say?' is the definition.
I don't know anything about this answer so I can't judge whether this works.

'work' is the wordplay.
I cannot quite see how this works, but
'work' could be 'double' (double is a kind of work) and 'double' is located in the answer.
The remaining letters 'leadalife' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).

'as' is the link.

Can you help me to learn more?