The famous DJ referred to Biebs as a "clown on a pedestal" in his younger years.
The Hobbit star allegedly tried to punch the Biebs with his fist instead of his words at an Ibiza restaurant when Justin reportedly said something rude about Bloom's former wife, Miranda Kerr.
During a 2013 web chat with The Sun, the Entourage producer had some unsolicited advice for the singer: "Justin, are you listening? Don't be so naughty. Be a nice boy...Stop smoking all that weed, you little bastard."
The Neighbors star is decidedly not a Belieber and took to Twitter to call the crooner a "piece of s--t," due to the Biebs' numerous arrests.
During a press conference for 2013 Billboard Music Awards, the blonde beauty was quick to dismiss the question when asked her thoughts on Bieber winning the Milestone Award.
The former Nickelodeon star claimed Justin "tried" to crash his album release party, but he ultimately conceded, saying, "There's no real beef."
The former commander in chief quickly forgave Bieber for spraying cleaning fluid onto a his picture and saying, "F--k Bill Clinton!" Stating, "If that is the worst thing you have ever done, all is well."
Kid said watching Justin "is 100 percent like watching Vanilla Ice all over again." Meaning? "The kid's young. He's got some money. He's got the world in his hands. It's just kind of sad to see him go down this trajectory."
"Put a f--king shirt on," the actress exclaimed on Twitter causing at least one Belieber to respond, "Put your shirt over your mouth."
No Taco Bell breakfast burritos for the Biebs because president Brian Niccol said he wouldn't be bringing them to Canada until they "take Justin Bieber back!"
The CSI star described the Biebs as "kind of a brat," after working with him on a CBS drama.
The London Evening Standard asked the rocker what he thought Bieber's tardiness and he said, "Do it once, you can be forgiven. Do it enough times and shame on you....It's really not cool—you're an a--hole. Go to f--kin' work!"
The Mad Men star went off on Justing during an interview with Men's Fitness "Look at Bieber or whoever," he said. "You're like, 'What the f--k, man? What are you doing? Why?' There's no one telling those people no, and it's a shame."
The Biebs was upset he didn't receive a Grammy nod last year to which the Black Keys drummer said the awards are "for music and not for money. And [Justin's] making a lot of money. He should be happy, I guess."
MORE PHOTOS: See the Biebs shirtless!