Anthony Joshua has pulled out of his 31 January showdown with American heavyweight Kevin Johnson after suffering a back injury.
The unbeaten Joshua, 25, underwent a scan which revealed a pars stress fracture and withdrew from the fight after seeking medical advice.
The heavyweight initially suffered the injury in his November victory over Michael Sprott but is expected to resume training in time for his next bout on 4 April in Newcastle.
"I trained so hard over Christmas and the press conference with Johnson was so lively that I was really looking forward to putting in a great performance," Joshua told Sky Sports.
"It's bad news for myself and for the fans that have bought tickets. I hope to be able to put on a fan zone at the weigh-in and the fight itself to meet the fans.
"I will be competing many times this year, but this injury is something that I need to get sorted as soon as possible."
Joshua has recorded 10 stoppages in his first 10 fights but was expected to be handed a sterner test in Johnson. While the veteran American is no longer in the world title hunt, he has never been knocked out despite past meetings with the likes of Tyson Fury, Manuel Charr and Vitali Klitschko.