Billy Joel has opened up about a dark period in his life, revealing that he attempted suicide twice and fell into a coma after having an affair with his best friend's wife.

The Affair that Changed Everything

In his early 20s, Joel was in a band called Attila with his best friend Jon Small. Joel moved in with Small, his wife Elizabeth Weber, and their son. However, things took a turn when Joel realized he was in love with Elizabeth.

"Bill and I spent a lot of time together," Elizabeth said in the documentary. "It was a slow build." But when Small realized something was up, Joel confessed his feelings, saying, "I'm in love with your wife."

The Aftermath

The affair led to the end of Attila and the end of Joel's friendship with Small. Joel felt guilty and started drinking, which marked the beginning of a downward spiral for the star. He eventually ended up marrying Elizabeth from 1973-1982.

"I had no place to live. I was sleeping in laundromats and I was depressed, I think to the point of almost being psychotic," Joel said in the documentary. "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."

The Suicide Attempts

Joel's sister, Judy Molinari, gave him sleeping pills to help him sleep, but he took all of them and fell into a coma for days. After waking up, he attempted suicide again by drinking a bottle of lemon Pledge, but was saved by Small.

"Even though our friendship was blowing up, Jon saved my life," Joel said.

Checking into an Observation Ward

After the suicide attempts, Joel felt like a "lost soul" and checked himself into an observation ward. The experience was life-changing for Joel, who was released within a couple of weeks.

"I got out of the observation ward and I thought to myself, you can utilize all those emotions to channel that stuff into music," he said.

The Documentary

The first part of Joel's documentary, "Billy Joel: And So It Goes," premiered at the Tribeca Festival in New York City, where he revealed his dark past.

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Read more about Billy Joel's tough childhood and his struggles with depression here.