Liverpool's Rocky Fielding will face Saul 'Canelo' Alvarez at Madison Square Garden in New York on 15 December.
Fielding, 31, won a version of the WBA world super-middleweight title in his last bout, beating German Tyron Zeuge.
Alvarez has held world titles in two weight divisions but has not contested a world crown at super-middleweight.
The Mexican, 28, goes into the bout off the back of two middleweight contests with Gennady Golovkin.
Alvarez, who drew controversy for two failed drug tests he later blamed on contaminated meat in his homeland, represents the stiffest test of Fielding's career by some distance.
"Taking a big challenge more in my career and representing the WBC as 160lbs champion now I will fight for the world title for the 168lbs," tweeted Alvarez, who still holds the WBC and WBA titles at middleweight.
Fielding will put his WBA 'regular' title on the line. The WBA recognises a 'regular' and 'super' champion - Liverpool's Callum Smith, who inflicted the only defeat of Fielding's career in 2015.
Fielding, 31, won a version of the WBA world super-middleweight title in his last bout, beating German Tyron Zeuge.
Alvarez has held world titles in two weight divisions but has not contested a world crown at super-middleweight.
The Mexican, 28, goes into the bout off the back of two middleweight contests with Gennady Golovkin.
Alvarez, who drew controversy for two failed drug tests he later blamed on contaminated meat in his homeland, represents the stiffest test of Fielding's career by some distance.
"Taking a big challenge more in my career and representing the WBC as 160lbs champion now I will fight for the world title for the 168lbs," tweeted Alvarez, who still holds the WBC and WBA titles at middleweight.
Fielding will put his WBA 'regular' title on the line. The WBA recognises a 'regular' and 'super' champion - Liverpool's Callum Smith, who inflicted the only defeat of Fielding's career in 2015.
