Saul 'Canelo' Alvarez will take on undisputed light middleweight champion Jermell Charlo in Las Vegas on September 30, the super middleweight champion announced on social media on Friday.
Alvarez, who currently holds all four belts in his division, posted a photograph of the pair on Twitter with the headline 'Undisputed v Undisputed'.
The Mexican, widely viewed as the leading pound-for-pound fighter in the world, last fought on May 6, when he outpointed English fighter John Ryder to record his 59th victory in 63 professional fights.
The announcement means Charlo's anticipated clash with Australian Tim Tszyu will not happen ahead of a deadline imposed on the American by the World Boxing Organisation, leaving the American at risk of being stripped of that belt.
Charlo last fought in May 2022 when he recorded a 10th round knockout of Argentina's Brian Castano in California.