I would so lie about hero-worship (7)
I believe the answer is:
idolise
'hero-worship' is the definition.
(I know that hero-worship can be written as idolise)
'i would so lie about' is the wordplay.
'i would' becomes 'I'd'.
'about' is an anagram indicator.
'so'+'lie'='solie'
'solie' is an anagram of 'olise'.
'id'+'olise'='IDOLISE'
(Other definitions for idolise that I've seen before include "Doilies to worship" , "Pay excessive attention to" , "Hero-worship, revere" , "Revere (someone) greatly or excessively" , "Pay inordinate attention to" .)