Usher and Justin Bieber
Usher is not happy with the person Justin Bieber has turned into.Getty

R&B singer Usher is reportedly not happy with the person Justin Bieber has turned into.

In the latest issue of Billboard magazine, the 36-year-old Voice mentor, who has supported the Baby singer ever since Scooter Braun discovered him at the age of 13, admitted that he gets upset with Bieber's trouble-causing behaviour.

"Our relationship is more man-to-man now. He's making his own decisions and it's important to show support. I can say I'm not happy with all the choices my friend has made, but I'm supportive of him. I try my hardest to give as much positive reinforcement as I can. I'll punch him in the f***ing chest when I need to, and give him a hug and kiss when I need to. It's more than just mentoring. I love the kid," he said.

Usher previously came to Bieber's defence when footage of the 20-year-old singer repeatedly using the "N-word" while telling a racist joke emerged.

"At my core, I am a person that supports growth and understands without judgment, that growth often comes as a result of pain and continues effort," Usher posted on his Instagram account.

"As I have watched Justin Bieber navigate difficult waters as a young man, I can tell you that he hasn't always chosen the path of his greatest potential, but he is unequivocally not a racist."

"What he was 5 years ago was a naive child who did not understand the negative power and degradation that comes from playing with racial slurs. What he is now is a young man faced with an opportunity to become his best self, an example to the millions of kids that follow him to not make the same mistakes," he concluded.