JLS fans with tickets for the Titanic Slipways concert in Belfast next week have been left gutted as they seek to get their money back.
No official reason has yet been given to explain why the event was pulled.
The charity was due to benefit by up to £200,000 from ticket sales, which it earmarked for the completion of Daisy Lodge respite centre in Newcastle, Co Down.
Tickets for the Belfast concert are fully refunded through Ticketmaster.
Last night NICFC chief executive Gillian Creevy said: "We are very disappointed this concert has been cancelled. We know everyone has been working very hard to support the work of the NI Cancer Fund for Children.
"I understand this decision was taken with extreme reluctance."