Singer turning into bear (8)
I believe the answer is:
baritone
'singer' is the definition.
(I know that baritone is a type of singer)
'turning into bear' is the wordplay.
'turning' indicates an anagram.
'into'+'bear'='intobear'
'intobear' anagrammed gives 'BARITONE'.
(Other definitions for baritone that I've seen before include "Second lowest male singing voice" , "One who can sing" , "Male singer in boater, strangely" , "Male singer looks odd in boater" , "Male voice between bass and tenor" .)