Acting with me could be so attractive (8)
I believe the answer is:
magnetic
'attractive' is the definition.
('magnetic' can be a synonym of 'attractive')
'acting with me could be' is the wordplay.
'with' means one lot of letters go next to another.
'could be' is an anagram indicator.
'acting'+'me'='actingme'
'actingme' anagrammed gives 'MAGNETIC'.
'so' is the link.
(Other definitions for magnetic that I've seen before include "What's attractive" , "Able to attract metal, or charismatic" , "Having the power to attract" , "Having the property of attracting iron" , "Very attractive or alluring" .)