Appearing on Howard Stern this week, Billy Joel admitted he once tried heroin (which he wrote about in his freaky 1982 song “Scandinavian Skies”) and that he considered forming a supergroup with Sting and Don Henley.

Here are some other surprising facts about the Piano Man.

He tried to commit suicide with furniture polish.

After breaking up with a girl at 21, Joel looked in his mother’s stuff for poison. He considered bleach, but the skull and crossbones put him off.

He figured furniture polish would taste better, but “All I ended up doing was farting furniture polish for a couple of days and polishing my mother’s chairs,” he told Details.

The experience inspired his song about the dark side, “The Stranger.”

He was a pretty good boxer.

Everett Collection (left); Getty Images (right)
After bullies knocked the books out of his arms when Joel was walking to his piano lessons, he took up boxing as a teenager and even won a few amateur fights in the Golden Gloves competition.

In one of his last bouts, he got his nose broken.

He left Woodstock because of foul toilets.

AP (2)
Joel spent a day and a half at the 1969 music festival in upstate New York because he wanted to see Jimi Hendrix, but the bathrooms were so disgusting that he left.

The nasty song ‘Laura’ is about his mother.

Joel’s drummer Liberty DeVitto confirmed that Rosalind Joel inspired the swirling, angry tune that contains such lyrics as “Laura/Calls me/in the middle of the night/passes on her painful information” and “I’m her machine/She can punch all the keys/She can push any button I was programmed through.”

DeVitto hinted that Laura became the title because it has the same number of syllables as “mother.”

And ‘Vienna’ is about a trip to see his father.

He barely knew his German father, Helmuth, later known as Howard, a classical pianist who fled Germany during the Holocaust and made his way to The Bronx, where Billy was born.

When Joel was in his 20s and in Europe, he hadn’t seen the old man in over a decade but heard his father was in Vienna, where the two had a visit.

‘Big Shot’ is about Bianca Jagger, sort of.

Getty Images
Joel has said that the song is a mockery of himself, but he told Howard Stern in 2010 that he wrote it after having dinner with Mick and Bianca Jagger, and imagined the lyrics describing Mick’s thoughts toward his then-wife.

He had a heavy-metal period.

Getty Images
In 1970, he was part of the duo Attila, which released one album, the cover of which features Joel dressed as a barbarian and surrounded by hunks of raw meat. He was 19 or 20 at the time.

Before that, two years after seeing the Beatles on “The Ed Sullivan Show,” Joel founded a band that did covers of British Invasion songs.

He’s an atheist but he believes in ghosts.

Charles Wenzelberg/NY Post (left); Shutterstock (right)
When he lived in East Hampton, Joel saw a 19th-century woman in his house, sitting and brushing her hair.

Despite being born to non-observant Jews, he attended Mass as a boy.

Getty Images
Growing up in Hicksville, LI, Billy had a lot of Italian-American and Polish-American Catholic friends, so he went to church with them on Sundays.

He even went to confession.

He graduated high school at age 43.

Everett Collection (left); WireImage (right)
He left Hicksville High without having completed his work, but in 1992 he turned in some missing essays and got his diploma.

He thinks he’s funny-looking.

Getty Images
“I don’t look like a rock-and-roll star,” he told Details. “I look like the guy who delivers the pizza.”

He has outsold Michael Jackson.

Getty Images (left); AP (right)
According to the RIAA, Joel’s US album sales stand at 81.5 million units, 6 million ahead of MJ. That puts him sixth all-time, behind only the Beatles, Elvis, Garth Brooks, Led Zeppelin and the Eagles.