Justin Bieber's wild behaviour has been blamed on constantly to trying to win his dad's approval, by one of the pop star's oldest friends
Cory Bernier, who watched Bieber grow up, said the 19-year-old is desperate to impress tattooed Jeremy Bieber, 38.
Bernier spoke out after the teen idol was released on bail after being caught street-racing in a Lamborghini following an alleged "drink and drugs" bender with his father at a rented Miami villa.
He said: "Justin has a very good heart but his judgement is being clouded by drugs and alcohol and a lot of it is to impress his dad."
He accused Jeremy of acting like a "stereotypical bad-ass" - and being a poor role model for the youngster.
He revealed: "The family is concerned about Justin but they don't believe he has a problem. He walks around without a shirt on but that's just ego - and that's his dad's ego too."
Justin was seen partying with Jeremy in Miami Beach's SET nightclub shortly before he was caught at 4.30am driving at twice the speed limit in the rented yellow sports car..
Jeremy, along with other members of the star's entourage allegedly used their cars to block traffic so his son could race against another car driven by his rapper friend Khalil Sharieff.
After being pulled over, Bieber is said to have told arresting officers he had drunk beer and smoked marijuana while also being under the influence of anti-depressants - before driving the Lamborghini.
He had no valid driving licence, failed a sobriety test at the scene, and allegedly unleashed a barrage of f-words at police.
In his defence, dad Jeremy responded on Twitter to his two million followers:
Justin - now worth around £80 million - was raised by single mother Pattie Mallette, who fell pregnant aged 17 and split from Jeremy 10 months after giving birth.
Reports suggest the star has recently cut off contact with Pattie, preferring to hang out with his father - who has remarried and has two more children.
Bernier, who still lives in Stratford, Ontario, where Bieber grew up, said: "He would be better spending more time with his mum. My message to Justin would be, 'Slow down and get help - you have your whole life ahead of you'."
Bieber's spokesman declined to comment on Bernier's claims.
But the singer's manager and mentor Scooter Braun, broke his silence with a message of support.
He tweeted: "@Justin Bieber love you and I will act in the manner of someone who truly cares."
Growing drug use
Justin's pals are also concerned that the pop idol may be taking the steroid Clenbuterol, which is fuelling his aggressive behaviour.
It is believed he has turned to the drug after finding out bodybuilders use it for muscle definition.
A source said: "As well as drinking and smoking weed, Justin's been taking steroids to give himself a six pack.
"His physique had gone from boy-like to muscled in a very short time and his moods have become wildly erratic.
Bieber has posted a picture of himself sitting on the roof of a people carrier following his jail release. Alongside was a photo of Jacko on a car roof after he pleaded not guilty to child molestation. He captioned it: "What more can they cay."
Police revealed on Friday that despite initial reports that Bieber appeared drunk he was later found to be below the legal drink-drive limit. However, he is still charged with driving under the influence of marijuana.