Unified middleweight world champion Gennady Golovkin has accepted a deal for a rematch against Canelo Alvarez, with the fight scheduled to take place in September.

A Wednesday deadline set by Alvarez's promoter Oscar De La Hoya appeared to have passed with no agreement in place, only for a sudden turn of events late in the evening.

"I'm happy to inform that we have a fight September 15!!!!" De La Hoya tweeted. 

The pair's first bout last September ended in a controversial draw, with judge Adalaide Byrd's scorecard of 118-110 in favour of Alvarez widely ridiculed.

A rematch was planned for May only for Canelo to withdraw after failing two drugs tests for banned substance clenbuterol in February.

He claimed it was a result of eating contaminated meat but was forced to withdraw from the original rematch after being given a six-month suspension, backdated to the first failed test on 17 February.

However, he is free to box again from 17 August and Golovkin has accepted a reportedly improved offer to stage the rematch.

Golovkin was the holder of three of the major world titles but was recently stripped of the IBF belt after declining to agree to fight mandatory challenger Sergey Derevyanchenko.

The Kazakh remains the unified WBC and WBA middleweight title holder. 

"This is just the beginning," tweeted Golovkin following the announcement.