Anthony Joshua and Francis Ngannou will earn eye-watering money for their fight in Riyadh, Saudi Arabia, on March 8.
The British heavyweight was to face Deontay Wilder, but that arrangement collapsed after Joseph Parker defeated the American just before Christmas.
Joshua will now face Ngannou, who almost claimed a shock win over Tyson Fury.
According to Sports Business Journal, Joshua will take home around £31 million from his clash with the former UFC star.
Ngannou would receive around half that amount at £16 million, which is double the amount that he made from his closely fought defeat to Fury last October.