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 and Elton John haven’t always seen eye to eye. During the newly released second part of HBO’s “Billy Joel: And So It Goes” documentary, Joel revealed how John’s public push for him to enter rehab caused a major rift between the two music superstars.

And So It Goes, which aired its second part on Friday, that he was ‘really hurt’ by comments made by Sir Elton. The duo had been on their Face to Face tour, which they kicked off in 1994,when Sir Elton addressed several cancellations in an interview with Rolling Stone.