Billy Joel has recalled how he attempted suicide and fell into a coma "for days" after having an affair with his friend's wife when he was in his early twenties.
In the first part of the new documentary Billy Joel: And So It Goes, which premiered at the Tribeca Film Festival in New York City this week, the Piano Man singer reflected on how he fell into a deep depression after it was revealed that he had been in a relationship with Elizabeth Weber Small.
Elizabeth was the then-wife of Billy's Attila bandmate, Jon Small.
"I felt very, very guilty about it. They had a child. I felt like a homewrecker," he said, according to People. "I was just in love with a woman and I got punched in the nose which I deserved. Jon was very upset. I was very upset."
Billy described how he was at the point of "almost being psychotic" and "in a lot of pain".
His sister Judy, who was a medical assistant at the time, gave him some sleeping pills to help him rest.
"But Billy decided that he was going to take all of them... he was in a coma for days and days and days," she explained. "I went to go see him in the hospital, and he was laying there white as a sheet. I thought that I'd killed him."
Later, Billy attempted suicide again - but Jon quickly took him to the hospital.
"Even though our friendship was blowing up, Jon saved my life," the 76-year-old shared, noting that he gained clarity and was able to recover while on the observation ward. "I got out of the observation ward and I thought to myself, you can utilise all those emotions to channel that stuff into music."
Billy and Elizabeth reconnected after a period of time and were married from 1973 to 1982.
Last month, the Uptown Girl hitmaker announced he would be cancelling his upcoming tour dates as he was suffering from normal pressure hydrocephalus (NPH) - which causes fluid to build within the brain and can affect cognitive ability and movement.
He wasn't in attendance at the debut screening of the documentary on Wednesday night.