Justin Bieber has said sorry for cancelling multiple appearances, but gave no reason as to why. Photo / Getty
Justin Bieber has apologised to fans after cancelling a string of planned appearances.
The Sorry hitmaker cancelled a series of performances - including an appearance on The Late Show With Stephen Colbert - without offering a proper explanation and has now taken to his Twitter account to say sorry to those people who were hoping to see him.
Later, he thanked his fans for their understanding, though he again declined the chance to explain the problem.
Gossip website TMZ said Justin has been on an emotional roller-coaster in recent weeks and simply could not continue with his hectic schedule.
The announcement comes shortly after it was reported Justin serenaded his ex-girlfriend Selena Gomez in a hotel bar.
The on/off couple were seen at the Montage Hotel in Beverly Hills, where Justin sang a number of songs, including My Girl and his own tune Sorry.
It comes after Justin recently admitted he will always love the singer.
"[She] is someone I love dearly. I'm never going to stop loving her. I'm never going to stop checking in on her," he said.
"I don't think if you end a relationship, you should end that, unless it was super toxic and you guys were hurting each other physically or mentally. We always respected each other and we still respect each other."
-Bang! Showbiz
The Australian site cited a 'heightened threat level' as the issue.