Billy Joel is opening up about a tough moment with longtime friend and tourmate Elton John. In the second part of the new two-part HBO Documentary, "Billy Joel: And So It Goes," the "New York State of Mind" singer shared how John's public comments that he needed rehab strained their friendship.

Billy Joel has never been shy about the fact that drinking played a role in his biggest heartbreaks — including the end of his marriage to Christie Brinkley. In her recent memoir, Brinkley wrote that “booze was the other woman,