Golovkin (38-0-1-KO34) and Alvarez (49-1-2-KO34) produced a controversial draw in their first meeting on September 16, with many favouring the work of the undefeated Kazakh.
The two fighters were originally scheduled to face other in a much-anticipated rematch for the WBA, WBC and IBF middleweight titles on May 5, before Alvarez withdrew from the fight in the wake of a failed drug test.
Alvarez returned a positive sample for trace levels of the decongestant Clenbuterol, which his promoter Golden Boy Promotions blamed on contaminated meat, and the Mexican was suspended for six months by the Nevada Athletic Commission in April.
Both sides have been locked in fierce negotiations in an attempt to revive the rematch, while Golovkin was stripped of his IBF title for failing to agree to a mandatory defence against Sergiy Derevyanchenko.
Golden Boy reportedly issued Golovkin a final offer of a 57.5-42.5 per cent split in favour of Alvarez and an agreement appears to have been finally reached between the two camps after De La Hoya announced the rematch on social media on Wednesday evening.
“I’m happy to inform that we have a fight September 15!!!! #CaneloGGG2,” wrote the former six-weight world champion.