From Joël Dufour's interview with Ray Charles' first band leader, Renald Richard, published in Soul Bag (January 2004, #176/177):
JD: Was your repertoire all R&B and jazz, or would Ray Charles sing a few standard ballads as well?Bunny Berrigan:
RR: He wrote the Bunny Berrigan version of I Can't Get Started as a feature trumpet solo, and he did a couple of other ballads - not many.
JD: Did he sing I Can't Get Started, or play it as an instrumental? Were you the trumpet soloist on that?
RR: I think that Ray sang on I Can't Get Started; however I played the trumpet solo exactly as Bunny Berrigan recorded it. Ray transcribed it for me.