Saul Alvarez will attempt to become a five-weight world champion when facing WBC cruiserweight title holder Ilunga Makabu in May.
The Mexican had been expected to return to light-heavyweight, an increase of seven pounds, for his next outing in six months time.
However, at the WBC convention on Tuesday, trainer Eddy Reynoso announced that the 31-year-old would instead move up to the 200lbs division to meet Makabu.
The WBC followed up Reynoso's statement by confirming plans for the bout, expected to be held on Cinco de Meyo weekend at the start of May.
Makabu, whose only defeat since 2009 came against Tony Bellew five-and-a-half years ago, has made three successful defences of his WBC crown since winning the belt in June 2019.