Mayweather re-established his position at the top of the game last May with a unanimous decision win over Robert Guerrero. He has been world champion at 130, 135, 140, 147 and 154 pounds, and is 5/14 favourite to win against Alvarez.
Tale of the tape:
Age: 36, born February 24, 1977.
Birthplace: Grand Rapids, Michigan, USA. Now lives Las Vegas, Nevada.
Record: 44-0 (26 KO).
Height: 5ft 8ins.
Weight: (not official weigh-in): 152 pounds.
Reach: 72 ins.
More top news
It's been a messy day for many with a mixture of heavy showers, thunder and blustery winds affecting parts of the UK.
£90,000 found under a bed in derelict house, by firefighters about to set fire to it in a training exercise.
Sturgeon has rejected the idea of a SNP-Tory coalition, stating if Tories can't win majority 'they don't deserve to be the Government.'