Or "session musician". The people who make the music you hear on TV and radio commercials, film soundtracks, or even your fave hit CD. Generally faceless, but here's part of one family tree: you see Will Lee on TV, but you've also heard him sing and play bass on commercials (you may also have seen him singing in the Orange Bowl halftime show a few years ago); Paul Shaffer got a big break in the 70s, after Roy Bittan's E Street Band duties took him out of the studio.