Anthony Joshua would no longer be defending his IBF and WBA heavyweight titles against Kubrat Pulev after the Bulgarian pulled out through injury.
The Bulgarian suffered a shoulder injury while training ahead of the title bout.
The tickets to the bout, which was scheduled for October 28, have already been bought by over 70,000 boxing fans.
Joshua will take on Carlos Takam, the next challenger in line.
Cameroonian-French Takam, 36, on Monday night finalised a deal to step in at late notice.
“I received a call late afternoon to inform me that Pulev had injured his shoulder and may be ruled out of the fight – this was later confirmed by his doctor.
“IBF rules state that the mandatory will go to the next fighter in line which is Carlos Takam.
“When the Pulev fight was announced I made a deal with Takam’s team to begin camp and be on standby for this fight. When I called them this evening they were overjoyed and good to go.
“It’s a difficult position for AJ having prepared meticulously for the style and height of Pulev, he now faces a completely different style and challenge in Takam – this hasn’t happened in his career before but he is ready for all comers on October 28,” Joshua’s promoter, Eddie Hearn, said.