ans were left angry and disappointed after N-Dubz were forced to cancel their show in Nottingham “at the very last minute” due to illness.
The group apologised to those who had travelled for the concert, but said singer Dappy had been advised by doctors to rest and would be unable to perform.
The show is part of their The Back To The Future tour which began on November 7 in Newcastle and is due to finish in Manchester on Saturday November 19.
The sudden announcement was made moments before N-Dubz were due to take to the stage at 9pm on Tuesday, after support acts had performed, via a large on screen message.
“We’re so sorry we had to cancel the show tonight,” N-Dubz later wrote on Twitter.
“We tried to do everything possible to make the show happen, but a doctor advised at the very last minute that Dappy was unable to perform and needed to rest tonight…
“The O2 Arena show tomorrow (November 23rd) and the rest of the tour will still be going ahead. We will make a further statement after Dappy has seen the doctor again tomorrow morning.”
They added: “We had to take this advice seriously and consider Dappy’s health so that the rest of the tour can happen, which has so far been amazing.
“We’re deeply sorry to all the fans who travelled to see us tonight and promise to make it up to you with a new rescheduled date for the show.”
Fans reacted with anger and disappointment online, with some social media users describing the news as “appalling” and a “joke”.
Others questioned why the band had allowed fans to arrive and the support acts to go ahead if they had been aware of Dappy’s condition.
Hours before the show, Dappy posted to his Instagram story that his voice was “basically gone” as a result of doing “too many shows back to back”.
The Back To The Future tour marked the end of N-Dubz’s decade-long hiatus.
The band consists of rappers Dappy, real name Costadinos Contostavlos, his cousin Tulisa Contostavlos and Fazer, real name Richard Rawson.
The band’s first two albums, Uncle B and Against All Odds, were certified platinum in the UK.
In 2009 they hit No 1 on the UK Singles Chart with Number One, a collaboration with Tinchy Stryder.
They have won four Mobo awards, including best newcomer in 2007, best album and best act in 2009 and best song in 2010 and were nominated for the Brit award for best British single in 2010.
The group originally announced plans for a two-year hiatus to focus on their solo careers in 2011 but have not released any new material since.