Justin Bieber has left fans questioning whether he's coping with his immense fame.

For a while the 21-year-old was better known for his pop brat ways than new music, but Justin seemingly turned his attitude around with the release of his smash hit record Purpose at the end of 2015. However his legions of supporters, known as Beliebers, appear worried after Justin posted a cryptic message on his Instagram account.

"The fear is uncontrollable I can't wrap my head around when it comes – it goes but it ways (sic) on me. When will the fear stop? I don't know if it ever will - Justin Bieber," read the message, which was left uncaptioned.

Fans were quick to show their support, with one commenting: "We love you and we support you, no matter what. The fear never stop but you can with everything. Your family, friends and beliebers (sic) are with you. Don't forget that."

Another told him: "nothing can break you! you are stronger than this. pull through and it will be worth it. we love you and support you endlessly."

The year had got off to a good start for Justin, who rung in 2016 with rumoured girlfriend Hailey Baldwin in St. Barts. He's also set to embark on his Purpose world tour, and he stormed the Nickelodeon Kids' Choice Awards nominations.

However it's not all been plain sailing. As well as being involved in a car crash in LA earlier this month (Fab16), Justin's ex Selena Gomez has declared she's done with their on-off romance.

“I’m so exhausted,” she told W magazine. “I honestly am so done. I care about his health and wellbeing. But I can’t do it anymore.”