Saturday's bout and its billing as the richest fight in history will see Floyd Mayweather attempt to unify his WBA light middleweight title against WBC 154-pound champion Saul 'Canelo' Alvarez at the MGM Grand Garden Arena in Las Vegas.
Pound for pound number one at 36, Mayweather is back in the ring for the second time in five months.
Canelo turned pro at 15 and wins with a hard-hitting style and a powerful body attack.
Alvarez signed with Golden Boy Promotions in 2010, and his impressive unbeaten record of 42, no losses and one draw rivals that of Mayweather on 44 wins, no losses and 26 Knock Outs.
More top news
Thickening cloud and rain stalling across Wales and southwest England through tomorrow