Brad and Angelina originally in love (4)
I believe the answer is:
nail
'brad' is the definition.
(I've seen this before)
'angelina originally in love' is the wordplay.
'originally' indicates taking the first letters.
'in' is an insertion indicator.
'love' becomes 'nil' (I've seen this before).
The first letter of 'angelina' is 'a'.
'a' going inside 'nil' is 'NAIL'.
'and' is the link.
(Other definitions for nail that I've seen before include "Growth on digit" , "one under the hammer" , "Bring down" , "Spike, tack" , "Perfectly execute" .)