This dude's was an opera singer that did more than just opera. I think he's alive but retired? I should probably look this up.
Anyhow, there are a zillion versions of this song and it has been riffed on so many times... You could probably find 100 versions of this on YouTube - but (in my opinion) this one is the absolute best:
Wait for it... Give it a minute...
I should record it to share it, but I do a cover that's using his vocal style - while providing more musicality with a classical guitar.