Justin Bieber has poured his heart out in an open letter to his fans after cancelling the rest of his world tour.

The Canadian pop star last week announced he was pulling the final dates of his Purpose tour “due to unforeseen circumstances”.

Bieber, 23, has addressed the cancelled tour for the first time, and said it was due in part to wishing to have a “sustainable” career and future.

He told his fans he was “grateful” for the journey with them, for his previous tours and for going through “this life” with them.

The Sorry hit-maker wrote: “I have let my insecurities get the best of me at times, I let my broken relationships dictate the way I acted toward people and the way I treated them!”

He added that he let “bitterness, jealousy and fear” run his life.

“I am extremely blessed to have people in the past few years help me build my character back up reminding me of who I am and who I want to be,” he said.

Bieber said he is “VERY aware” he will never be “perfect” and said he will keep making mistakes.

“But what I’m not gonna do is let my past dictate my future,” he added.

“What I’m not gonna do is be ashamed of my mistakes.”

“I wanna be a man that learns from them and grows from them.!! I want you all to know this tour has been unbelievable and has taught me so much about myself..

“I am reminded of how blessed I am to have a voice in this world. I’ve learned the more you appreciate your calling the more you want to protect your calling. Me taking this time right now is me saying I want to be SUSTAINABLE.

“I want my career to be sustainable, but I also want my mind heart and soul to be sustainable. So that I can be the man I want to be, the husband I eventually want to be and the father I want to be.”

He said he wanted his message to act as an opportunity for people to “know where I am coming from”.

Bieber signed off apologising for the “VERY GRAMMATICALLY INCORRECT” post, and added: “BUT I THINK THERES SOMETHING SPECIAL ABOUT IMPERFECTIONS!!”

The singer had been touring in support of his album Purpose for the past 18 months, playing more than 150 shows, including the recent British Summer Time festival in London, but has axed the final 14 scheduled performances.

His upcoming shows included stops in Asia, the United States and Canada.