The big fight will be shortly starting in Las Vegas, at the MGM Grand Hotel and Casino. You can watch the fight on Pay-Per-View with HBO.
It looks set to be a great fight, Ortiz, 24, is looking strong and has had a great victory over Andre Berto which made him a champion.
Mayweather was watching the fight ringside back in April. Ortiz was knocked down in the second and sixth rounds, but managed to get the decision.
Mayweather, 34, will be receiving a crazy $25 Million for the fight, plus a percentage of the Pay-Per-View revenue.