Rhapsody in Blue composer (8)
I believe the answer is:
gershwin
'rhapsody in blue composer' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for gershwin that I've seen before include "Ira and George, US brother composers" , "Ira -; US lyricist" , "US composer" , "I Got Rhythm composer" , "SECOND PART OF 14" .)