The Sun reported that the 18-year-old rubbished rumours that he had drunk liquid codeine with friends and US websites buzzed with pictures purportedly showing him and rappers Lil Twist and Lil Za with a bottle of codeine syrup on their table.

Earlier reports claimed he had started dabbling in marijuana while out with his rapper pals. The As Long as You Love Me crooner blasted the speculation on Twitter, posting: "Some of these rumours about me are getting a little out of control now.

"Don't believe the BS. Gonna focus on the positive. Understand that rumours come with the territory but I'm gonna stay me."

He later added: "Focus on the music. U wanna know what I'm about it is all right there."

This weekend, he was spotted with Lil Za, in California, embarking on far healthier pursuits - including horse-riding and enjoying dinner at a crustacean restaurant in Los Angeles with rapper Tyga. He also reportedly found time for ex-girlfriend Selena Gomez, which sparked rumours of a reunion, following their break-up after a New Year fight in Mexico.

Gomez was spotted returning to her home in the wee hours of the morning, with Bieber's bodyguard following closely.