At one point, [Billy] said to me, 'You going deep?' And I said, ‘Yeah, and you know you’re going to go deep too,'" the film’s co-director Susan Lacy says.

The directors of "Billy Joel: And So It Goes" recently opened up about the making of the new HBO documentary and provided an update on the legendary singer’s health.

The result is an expansive examination of the man and his art - a career that includes six Grammys, a Tony, and enshrinement in both the Rock and Roll Hall of Fame and Songwriters Hall of Fame - covering five hours and featuring 110 of Joel's 121 songs. And that's the trimmed-down version. "It was much longer," Lacy says.