Chart-topping singer Ed Sheeran is stepping in "last-minute" to replace pop idol Justin Bieber at a music festival after the Canadian star pulled out "due to an unforeseen issue".

Sheeran is now headlining the Fusion Festival in Birmingham on Friday August 28 and the flame-haired hitmaker wrote on Twitter: "I know I said Wembley was my last UK show of this tour but my mate had a cancellation on his festival so I'm filling in last minute."

Bieber was set to perform that night - playing his first UK show since his disastrous tour two years ago - but on Tuesday he announced on Twitter that he would not be performing.

The Baby singer said: "To all my UK beliebers ... Due to an unforeseen issue I will be unable to perform at the Fusion Festival on August 28th.

"I support the Prince's Trust wholeheartedly and I am deeply disappointed I won't be able to perform.

"I look forward to the opportunity to give my UK beliebers a great show in the near future and hope to honour my commitment to Trust at that time."

Bieber's 2013 gigs at London's O2 upset fans after he started one concert late, leaving some of them stranded and others having to go home shortly after it began.

Another gig was disrupted when he left the stage mid-song after complaining of being "light of breath".

He was also forced to explain himself after he lashed out at a photographer following what he said had been a "rough week".

Glasgow Times:

Bieber, 21, explained in a series of messages on Twitter shortly after the outburst - during which he shouted obscenities on a London street - that his adrenaline was running high and he "let the paps get the best of me".

Meanwhile, Sheeran, 24, played three sold-out gigs at Wembley Stadium last month, becoming the first artist to perform at the stadium without the accompaniment of a band.

The concerts coincided with his return to top spot in the new Friday charts with his second album x for the fourth time.

Damien Sanders, event director for Fusion, said: "This is incredible news, when Ed heard that Justin Bieber had pulled out he contacted us and offered to step in at the last minute, this is an amazing gesture from an all-round great guy and Ed really has saved the day, we are all eternally grateful.

"We look forward to a spectacular show and are delighted to have secured one of the biggest acts in the world."

Sheeran said: "I'm delighted to be playing Fusion Festival after stepping in at the last minute to help out the guys at Fusion and support The Princes Trust. Birmingham crowds are always lively, so I can't wait to come back. See you in a few weeks!"

Bieber tweeted Sheeran, saying: "@edsheeran thanks buddy. I owe u one. UK there is no one better to step up. I will see u all soon. Until then enjoy Ed. No one better :)"