Just why Swedish machine-operator Sebastian Tamminen ended up with the Canadian pop star's name emblazoned over such a private place - in Times New Roman font - remains a complete mystery to him.
“My friends and I were in Magaluf in Spain drinking and we ended up kind of drunk,” Tamminen, aged 24, told The Local back in his home town of Smedjebacken.
“Then they had this awesome idea of getting some tattoos. They each had a diamond tattooed on one foot - but for some reason, I ended up with Justin's name on my ass. I can't remember everything: most of it's just darkness.”
Tamminen posted a photo of the tattoo on his Instagram page, much to the delight of his followers, who tagged the pop star in the post. It then made national news when it was picked up by the Swedish newspaper Expressen.
While admitting to being a Bieber fan, the machine-operator says he isn't too comfortable with having the pop star's name on his bottom.
“I like Justin's music but I don't like him tattooed on my butt,” he said.
His girlfriend was equally unimpressed. “At first she was, like, ‘Oh my God, what have you done?' But of course she thinks it's kind of funny.”
Nevertheless, Tamminen says he doesn't have any plans to get the tattoo removed just yet.
“I don't know what to do with it - I think I'll just let it be.”
If there's anything positive to be gained from his night on the tiles, it's the hope that the pop star himself will see this unusual tribute online.
“Let's hang out, Bieber!” said Tamminen - though he knows that his wish is unlikely to be granted.
Tamminen's tattoo is not the only one to hit headlines in recent months.
Last week, two young dairy farmers who raised eyebrows in Norway after one got a picture of a Norwegian Red cattle tattooed on his right buttock and the other got one on his left shoulder.
“The cow is the coolest. I work with them almost every day, so why not?” Magnus Line, 18, told The Local Norway when asked about his choice of bottom tattoo.
And earlier this year an 18-year-old Norwegian found fame world-wide after deciding to tattoo a McDonald's receipt onto his forearm.
READ MORE: Norway farmer tattoos cow on right buttock