Justin Bieber may have to find a new baby, baby, baby following reports his relationship with Selena Gomez in on the rocks.

The couple has been love's young dream for 18 months now, but they hit a rough patch after things got too serious, too quick.

The singers are still together, but they are heading towards a full-on split, according to The Mirror.

A source told the newspaper: "They might be young, but Justin and Selena's is a very adult relationship. They have had to grow up really fast because of the pressures of their careers.

"To begin with, their similar situations complemented each other, but now they seem to be drifting apart."

Justin shocked fans last month after telling them to back off while he waited for Selena at Pearson International Airport in Toronto, Canada.

And the insider insists the teen idol put himself at the mercy of flocking fans because he was so desperate to make up with the actress.

The source adds: "It's unusual for Justin to put himself on public display by doing something like waiting at an airport arrivals area because he knows he'll get mobbed, but things have been so patchy with Selena lately, he needed to make the effort."

Justin recently opened up about how his first snog with Selena was the best smooch of his life, despite insisting he wanted to keep his romance hidden from fans.

He told Fabulous magazine: "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.

"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.

"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 that separate. I don't have many things that I get to keep to myself but that's one thing. I'm very happy. And I know my fans just want to be happy for me."