Billy Joel attempted to end his life twice after having an affair with his best friend's wife in his early 20s.

According to People, The Piano Man opened up about a turbulent period of his life in part one of his new documentary, Billy Joel: And So It Goes, which premiered at Tribeca Festival in New York City on Wednesday (June 4).

The first part of the documentary focused on Joel's affair with Elizabeth Weber, who was, at the time, his Attila bandmate and best friend Jon Small's wife.

Weber appeared in the film and described her relationship with the "Uptown Girl" artist as a "slow build." She spent a lot of time with Joel in the '70s, and he eventually told Small that he was "in love" with his wife. Joel expressed guilt about what he'd done and was distraught.

"I felt very, very guilty about it. They had a child. I felt like a home-wrecker. 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."

The fiasco ultimately led to the demise of their band, and Joel turned to alcohol to tamper the pain of losing his friend.

"I had no place to live. I was sleeping in laundromats, and I was depressed. I think to the point of almost being psychotic. So I figured, 'That’s it. I don’t want to live anymore.' I was just in a lot of pain, and it was sort of like, why hang out? Tomorrow is going to be just like today is, and today sucks. So, I just thought I’d end it all."

His sister, Judy Molinari, worked at a medical facility and gave him pills to help him sleep when he expressed a need. She unveiled, in tears, that Joel "decided that he was going to take all of them" and "was in a coma for days and days and days."

"I went to go see him in the hospital, and he was lying there white as a sheet. I thought that I’d killed him."

The second time he attempted to end his life, Small, the man whose marriage he ruined, took him to the hospital and saved his life.

He eventually forgave Joel, and Joel checked himself into an observation ward for a couple of weeks to improve his mental health, which proved "life-changing."

The "My Life" artist ended up marrying Weber, and their relationship lasted from 1973 to 1982. He eventually learned how to transform his sorrows into lyrics that echoed through the ages.

Billy Joel: And So It Goes will be available to stream on HBO next month.

If you or someone you know is struggling with thoughts of suicide or substance abuse, call or text 988 or visit 988lifeline.org.

Brett 'Bside' Matthews