Conor McGregor and Floyd Mayweather face off on Aug. 26 at T-Mobile Arena in Las Vegas in a pay-per-view event expected to be the most lucrative prize fight of all time.
But how did we arrive at being on the precipice of a fantasy crossover fight nobody thought would ever happen?
BT Sport takes a closer look at the build-up ahead of the blockbuster bout between UFC star Conor McGregor and legendary boxer Floyd Mayweather on August 26, featuring interviews and analysis.
Watch the complete 24-minute documentary special above.