Justin Bieber is "definitely not yet a man" and cannot be considered an "adult artist".

According to Bieber's manager, Scooter Braun, the 18-year-old singer has made massive strides in his career – and although his latest album Boyfriend is more mature, the star "still needs guidance".

He told Billboard magazine: "Adult artist? Just because he's legal now doesn't mean he's an adult.

"He still needs guidance; he's still finding his way. He's no longer a boy, but he's definitely not yet a man."

Braun also said that he is proud of Bieber’s maturity in handling his career and massive fame. 

He added: "No one in the history of the world has ever grown up with the pressure that he has, being a solo artist that young, that famous, in a world with technology that exposes us 24/7.

"He was literally going through puberty in front of the entire world, with everyone expecting something from him and a lot people waiting for him to screw up.

"He's a fighter. I'm proud of him — how's he's stayed true to himself and taken control of the entire situation."

Bieber has previously revealed that he has to be constantly cautious and finds it "sad" that he cannot trust just anybody.

He said: "I mean, I keep my guard up a lot, because you know, you can't trust anyone in this business. That's what's sad. You can't trust anybody. I learned the hard way."