Justin Bieber has opened up on girlfriend Selena Gomez, describing the feeling he gets from their relationship as "butterflies and happiness".

The teen singer suggested to Fabulous magazine that he is in love with her - something he knows because of the feelings he gets from her. He said:

"What does love feel like? It feels good. If you're really in love then you should get butterflies. Butterflies and happiness, that's how I feel anyway."

He continued: "But I never like to throw it in my fans' faces. I love my fans and I'd never want to do that to them. It's my private life and I like to keep separate. I don't have many things that I get to keep to myself but that's one thing."

Bieber added that his first kiss with Gomez was his best ever. He said:

"My first kiss with Selena was the best of my life. It was in the car. It was scary and spontaneous and it was just awesome."

Watch a behind the scenes look at Bieber's 'Believe' below: