Justin Bieber thinks he is uncool.

The 'Baby' hitmaker admitted he doesn't understand why he is so popular with fans, calling their over the top reactions to him "crazy".

He said: "I'm not even that cool, like seriously. what is so cool like that you freak out. These girls crying, it's like I can't believe that, I'm so honoured that you're crying but, I don't know, it's crazy to me!"

However the 16-year-old singer - who recently released his autobiography 'First Step 2 Forever'- revealed he is happy to get attention from fans and said that he hopes to be an inspiration to people.

Speaking about why he decided to release a book at such a young age, he explained: "I wanted something with my own words. to describe what I'm going through and describe how I got here. I want people to look up to me, I want people to say, 'You know, I look up to you.'"

The singer added that fans will be surprised by how "funny" his book is.

He said: "The humour in it, it's just funny, it's fun. There are so many surprises in here that you're just going to be like, 'What?' and a lot of things people don't know about me."