Actor and duty nurse forced to admit date (10)
I believe the answer is:
understudy
'actor' is the definition.
(understudy is a kind of actor)
'duty nurse forced to admit date' is the wordplay.
'forced' indicates anagramming the letters.
'to admit' is an insertion indicator.
'date' becomes 'd' (common abbreviation eg in DOB, date of birth).
'duty'+'nurse'='dutynurse'
'dutynurse' is an anagram of 'unerstudy'.
'unerstudy' going around 'd' is 'UNDERSTUDY'.
'and' is the link.
(Other definitions for understudy that I've seen before include "One prepared to take over from leading actor" , "reserve?" , "Replacement" , "emergency role" , "one covers part" .)