One became notorious for their shocking behaviour while the other is... Marilyn Manson.
And the shock rocker has become embroiled in a bizarre feud with Justin Bieber over a mash-up t-shirt based on one of the 90s star's classic shirts.
He was fuming the Sorry singer wore the item of clothing on stage, but was even more unhappy when a version of it emerged which featured his young rival's logo on the back, the Daily Mail reports.
The egotistical rocker was particularly incensed that the vain pop pixie had the temerity to poke fun at his relevance to the current music market.
The singer, real name Brian Warner, told Consequence Of Sound: "He said to me 'I made you relevant again'. He was a real piece of s*** in the way he had the arrogance to say that.
"He was a real touchy-feely guy, too, like, 'Yo yo bro!' and touches you when he's talking.
"I'm like, 'you need to stand down, you're d*** height on me, okay? Alright? So stand down, son.'"
He claims he got his own back by duping the Baby star into believing he would sing with him.
Marilyn said: "I told him I'd be at his soundcheck at Staples Center to do Beautiful People. He believed that I'd show up, because he was that stupid."
And he claims he made sure he got all the proceeds from a mash-up version of the shirt which was being sold for $195 at Barney's last yearm, which featured the phrase, 'Bigger Than Satan... Bieber' on the back.
He said the Baby star boasted to him that it had been his idea to create the item of merchandise.
Cheekily the designer, Fear of God's Jerry Lorenzo, posted a message on social media where he claimed it was created with the permission of the Antichrist Superstar warbler.
He said on Instagram: "Thank you Marilyn Manson for signing off on the 'Bigger than Satan' x Justin Bieber tee. Thanks for understanding our approach and re-interpretation of your vision."
According to Marilyn, who some critics have called a poor man's Alice Cooper, he has since grabbed all the cash for the garment.
He said the duo "didn't even fight," adding: "They were just like, 'Yea, we already know, we did wrong, so here's the money.'"
The divine pop pixie seems to be going for another image these days, as the reformed naughty boy has been very public about his Christian worship of late.
He is also said to be close to Hillsong Church pastor Carl Lentz, with the pair supposedly being "nearly inseparable" in recent times.