Justin Bieber acts out to impress his father, according to a close family friend.

Cory Bernier - who is called 'uncle' by the star who he saw grow up - has insisted the 'Beauty and a Beat' singer is desperate to gain his dad Jeremy approval.

Speaking to the Daily Mirror newspaper, he claimed: ''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.''

Cory also insisted while the 19-year-old singer's family are ''concerned'' for the star - who was charged with drink driving, resisting arrest and drag racing in Miami in the early hours of Thursday morning (23.01.14) - he is emulating Jeremy's own ''ego''.

He added: ''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.''

Meanwhile, the star's recent wild behaviour is said to be the result of taking steroids.

According to reports in The Sun newspaper, sources close to Justin believe fat-burning drug Clenbuterol could be behind his rage.

An insider 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.''