Part of lover, actually ham! (7)
I believe the answer is:
overact
'ham' is the definition.
(ham can mean to overact)
'part of lover actually' is the wordplay.
'part of' indicates the answer is hidden within the clue.
'OVERACT' can be found hidden inside 'lover actually'.
(Other definitions for overact that I've seen before include "Play part exaggeratedly" , "Be excessive like fulsome thespian" , "pile it on" , "Be excessive on stage" , "Perform hammily" .)