Joel recorded this as a duet with Ray Charles, who was his favorite piano player/singer (in addition to their musical talents, the pair share something else in common: last names that sound like first names). When Charles showed up at the session, they met for the first time, and Joel was in awe. To break the ice and get to know each other, they each played piano for a while before recording the song.
When Ray Charles would meet someone for the first time, he would touch that person's face. When he did this do Joel, he said, "relax," since he could tell Billy was nervous.