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.

Billy Joel has opened up for the first time about the brain disorder that forced him to cancel all upcoming performances and tour dates. The music icon, 76, was diagnosed with Normal Pressure Hydrocephalus (NPH) in May. The rare disease can cause problems walking, which is especially problematic for a performer like Joel.

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.

He didn’t see the film until it was finished, so he stuck by that, and we took that as permission to tell the real story about Billy Joel.”

In a revealing podcast interview, Joel discusses his balance problems and brain disorder diagnosis with Bill Maher, sharing personal insights.