Ewe turns out to be supplier of milk (3,5)
I believe the answer is:
wet nurse
'be supplier of milk' is the definition.
'ewe turns out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'ewe'+'turns'='eweturns'
'eweturns' with letters rearranged gives 'WET-NURSE'.
'to' is the link.
(Other definitions for wet nurse that I've seen before include "Woman to help mum" , "Child-minder" , "feeder" , "Milk supplier" , "Coddle" .)