Composer's new look (7)
I believe the answer is:
novello
'composer's' is the definition.
(composer Ivor Novello)
'new look' is the wordplay.
'new' becomes 'novel' (similar in meaning).
'look' becomes 'lo' ('lo' is an archaic exclamation meaning 'look!').
'novel'+'lo'='NOVELLO'
(Other definitions for novello that I've seen before include "See 8" , "Welsh composer, Ivor (1893-1951)" , "Ivor --, songwriter" , "Ivor --, Welsh singer, actor, composer" , "Ivor --, composer/actor" .)