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
The Brits saw two awards handed to the late David Bowie and tributes to George Michael. Here is a full list of the winners.
Regularly getting in more than nine hours in bed could be an early warning sign of the disease, say scientists.
Bradley Lowery has a rare form of cancer and although he's having treatment it will only give him more time.