Recently I got to know a cellist who looked quite hot when he played the cello. Away from his instrument he wasn't that amazing. Not bad looking, but certainly not hot. And once he opened his mouth to talk, well, the illusion was completely shattered.
This is not the first time that I've met someone who looks way hotter when they're playing an instrument. Why is this? They don't even have to especially amazing at their instrument, just capable enough to do the job they're there to do. Weird.