Lukas Graham on Growing Up Using a 'Nudist, Unisex Bathhouse' in Copenhagen

— -- The lyrics to Danish band Lukas Graham's big hit of the year "7 Years" was inspired by the childhood of lead singer Lukas Graham Forchhammer.

The singer grew up in Christiania, a part of Copenhagen where many live by choice in ramshackle homes with no heat or bathrooms. The singer said that for years his house didn't even have indoor plumbing -- and he liked it that way.

"I remember getting a toilet in our house," Forchhammer, 27, told ABC News. "I remember sharing a bedroom with my sister and my little sister was sleeping in my mom and dad’s room. We had two bedrooms upstairs and one big room downstairs with kitchen [and] living room...I remember getting the toilet in the bathroom, and I found it so weird showering in our own house!"

Prior to that, Lukas said, he and his family would go to a public bathhouse, like everyone else in Christiania, which he enjoyed.

"Our bathhouse was awesome!" Lukas recalled. "You’d meet all your friends and your friends’ brothers and sisters. It was like a nudist, unisex bathhouse, three hot showers, two cold showers, a big wood-fired sauna -- like, luxury bath facilities. Like, we had a spa for a bathroom my whole childhood! And it was free for kids and you’d pay, like, one dollar for a grown-up."

Even now, as an international pop star, Lukas enjoys going back home and using the bathhouse.

"Now I think I pay four bucks for my bath, I pay two bucks for my towel. So six bucks, I get to use a sauna!" he raved. "I find it amazing."

Lukas admitted that his upbringing was a bit odd, though. For example, in progressive, liberal, Christiania, weed and hashish are used and sold freely. Hard drugs are banned, however.

"It’s very magical," said Lukas. "We have the lowest violence rate in the inner city because people there take care of each other and watch out for each other. But it’s a trippy place!"