Muslim star with new single (5)
I believe the answer is:
sunni
'muslim' is the definition.
(I know that Sunni is a type of muslim)
'star with new single' is the wordplay.
'star' becomes 'sun' (the Sun is a star).
'with' means one lot of letters go next to another.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'single' becomes 'i' (one).
'sun'+'n'+'i'='SUNNI'
(Other definitions for sunni that I've seen before include "Form of religion" , "Indian fig tree with aerial roots" , "Member of another Muslim sect" , "One branch of Islam" , "Islamic faction" .)