With those big brown eyes and boyish charm, Justin Bieber appears adorably innocent. But it turns out the teen heartthrob is tougher than he looks, a lesson one fan learned the hard way!
"What lesson did you learn?" INSIDE EDITION's Diane McInerney asks 15-year-old Kevin Kristopik.
"Don't mess with a celebrity," he says.
Kristopik had a case of Bieber fever and wanted to get in touch with the star, so he hacked into the Facebook account of one of Bieber's closest friends.
"What were you thinking, hacking into someone else's account?" McInerney asks.
"I thought I was just having fun, just messing around," says Kristopik.
He was actually able to find Bieber's cell phone number on the Facebook page and made the mistake of calling and texting the star about 30 times.
The pop star became alarmed and fought back.
"He decided to tweet my cell phone number to about 4.5 million of his followers," says Kristopik.
Bieber posted Kristopik's cell phone number on his hugely popular Twitter page for millions of fans to see, writing: "Everyone call me 248-xxx-xxxx :) or text."
"I think I received about 30,000 text messages and probably around the same amount of calls," Kristopik says. "It was literally every second, if I denied a call, a call would pop back up, text messages, my notifications just kept coming up."
"I guess I kind of deserved some of it, but I think he went too far," Kristopik says. He tells INSIDE EDITION he is still a Bieber fan, but says, "I guess he needed to get me back and he did."
Justin Bieber has now taken Kristopik's number off his Twitter page.