Alvarez, 32, retained the belts against Gennady Golovkin last time out, outpointing his old rival in September, and now the Mexican defends the gold in his home country of Mexico.
Ryder is the challenger, looking for his fifth straight win and to build on a stoppage victory over Zach Parker, a result that saw the Briton win the WBO interim title in November.
Ryder, 34, is set for his toughest test yet as he takes on Canelo in Guadalajara, in a main-event bout.
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When is it?
The fight will take place on Saturday 6 May at the Estadio Akron in Guadalajara, Mexico.
The main card is scheduled to begin at 12am BST on Sunday 7 May (4pm PT, 6pm CT, 7pm ET on Saturday).
Ring walks for the main event are expected at approximately 4am BST on Sunday (8pm PT, 10pm CT, 11pm ET on Saturday).
How can I watch it?
The event will stream live on subscription service Dazn in the UK and worldwide, and on Dazn pay-per-view in the US and Canada.
Canelo – 1/12
Ryder – 13/2
Draw – 22/1
Full card (subject to change)
Saul “Canelo” Alvarez (C) vs John Ryder (WBA [Super], WBC, IBF and WBO super-middleweight titles)
Julio Cesar Martinez (C) vs Ronal Batista (WBC flyweight title)
Steve Spark (C) vs Gabriel Gollaz Valenzuela (WBA Intercontinental super-lightweight title)
Nathan Devon Rodriguez vs Alexander Mejia (featherweight)
Oleksandr Gvozdyk vs Ricards Bolotniks (super-middleweight)
Bek Nurmaganbet vs Argenis Espana (super-middleweight)
Lawrence King vs Elio German Rafael (super-welterweight)
Johansen Alvarez Suarez vs Johan Rodriguez Arreguin (super-featherweight)
Abilkhan Amankul vs Jesus Moroyoqui Palomares (middleweight)
Carlos Emiliano Rojo vs Fabian Trejo Rivera (super-welterweight)
Jesus Larios vs Alejandro Curiel (featherweight)
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