On the Verge of Rock Stardom

On a sooty, dank spring afternoon in March, the musician Cameron Winter sat hunched over a portable keyboard inside a rehearsal studio in a nondescript neighborhood of central Los Angeles. Mr. Winter, 23, was rehearsing for an appearance on “Jimmy Kimmel Live!” the next evening, and was teaching four middle-aged horn players his song “Drinking Age,” a melancholic ballad off his debut solo album, “Heavy Metal.”

At first, they struggled to find their chemistry — partly because the five musicians deciphering a structurally amorphous piece of music did not know one another, and partly because the horn players, all women, stood in a clump off to one side.

Mr. Winter was not sure he wanted them there at all. The Kimmel team had suggested he choose something more entertaining and TV friendly than Mr. Winter sitting with his 6-foot-3 frame hunched at a piano. Also, maybe he could play something other than a whiny dirge?

“My suggestion was I get a bloody nose onstage,” Mr. Winter said.

As a compromise, they agreed: No bloody nose and Mr. Winter could choose the song, with the addition of a brass quartet to fill it out.

As the rehearsal progressed, the singer’s well-mannered-Brooklyn-boy temperament triumphed, and a big-sister energy emerged from the four women toward this shaggy burgeoning star in his corduroy bomber jacket and fan-made T-shirt.