Tea with, perhaps, Eva's companion (8)
I believe the answer is:
chaperon
'companion' is the definition.
(thesaurus)
'tea with perhaps eva's' is the wordplay.
'tea' becomes 'cha' (cha is a type of tea).
'with' means one lot of letters go next to another.
'perhaps eva' becomes 'Peron' (Eva Peron, wife of Argentine president Juan Peron).
'cha'+'peron'='CHAPERON'
(Other definitions for chaperon that I've seen before include "Accompany and look after" , "One who accompanies and supervises" , "Duenna; look after" , "One accompanies the vulnerable" , "One accompanies to supervise" .)