I am England's new star (7,3)
I believe the answer is:
leading man
'star' is the definition.
(I've seen this before)
'i am england's new' is the wordplay.
'new' is an anagram indicator.
'i'+'am'+'england'='iamengland'
'iamengland' anagrammed gives 'LEADING MAN'.
(Other definitions for leading man that I've seen before include "Principal actor" , "Chief actor" , "megastar?" , "Star" , "top fellow on stage" .)