Singer entertaining queen, for example, reveals a different side (5,3)
I believe the answer is:
alter ego
'a different side' is the definition.
(a different side of someone)
'singer entertaining queen for example' is the wordplay.
'singer' becomes 'alto' (alto is a kind of singer).
'entertaining' indicates putting letters inside.
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'for example' becomes 'e.g.' (synonyms).
'er'+'eg'='ereg'
'alto' placed around 'ereg' is 'ALTER EGO'.
'reveals' is the link.
(Other definitions for alter ego that I've seen before include "A person's secondary personality" , "Other half" , "Hidden or second self - in Latin" , "To regale other self" , "bosom buddy" .)