Justin Bieber thinks he is a ''responsible'' young adult.

The 18-year-old 'As Long As You Love Me' singer - who was recently accused of being out of control after being pulled over by police and amid rumours he regularly smokes marijuana - claims that although he is enjoying himself, he hasn't done anything wrong.

The Canadian star told the 'Late Night with Jimmy Fallon' show on Tuesday (05.02.13): ''I don't do anything. I promise. It looks bad. You see pictures of me getting pulled over, but really the tints are really dark ... I need dark tints because I don't want to cause accidents because people want to take pictures. I just thought it would be more safe for everyone else if I had dark tints. I'm thinking about other people. I'm having fun being 18 and enjoying my life and being responsible.''

Meanwhile, Justin has laughed off rumours he cheated on Selena Gomez with Rihanna before their split in December.

According to Life & Style magazine, a source claimed the ''real'' reason behind the on/off couple's break-up was that she ''heard the shocking news that Justin had cheated on her'' repeatedly with the 'Diamonds' singer.

Justin's new album 'Believe Acoustic' has hit number one in the US, making him the first artist to achieve five number one albums under the age of 19.

He thinks the record will prove his real talent to critics.

He said: ''It's just good music. It just shows that I wasn't made, I was found on YouTube and it shows people music is music. That's what you need to focus on - listening to the music. I'm an artist. I'm not - I'm a singer and I want to show people what I love to do.''