Sources: Gennadiy Golovkin, Ryota Murata agree on Dec. 29 title bout in Japan

Gennadiy Golovkin and Ryota Murata have agreed to a deal for a Dec. 29 middleweight title unification bout at Saitama Super Arena in Saitama, Japan, multiple sources told ESPN. A formal announcement is expected next week.

The fight will take place just outside Murata's hometown, Tokyo. The Olympic gold medalist is a major star in Japan and the biggest boxing attraction in the country.

The sides had an agreement in principle months ago but GGG still needed to strike an amended deal with streaming service DAZN. The longtime 160-pound champion signed a six-fight pact with DAZN worth approximately $100 million in early 2019.

However, that deal hinged on DAZN's belief that GGG would fight Canelo Alvarez a third time. The boxers competed twice - 2017 and 2018 - major events that were incredibly competitive. The first fight was ruled a draw with Alvarez earning the decision in the second contest.

With GGG and DAZN now on the same page, Golovkin will look to once become unified middleweight champion.

ESPN's No. 2 middleweight, Golovkin (41-1-1, 36 KOs) hasn't competed since a December TKO victory over fringe contender Kamil Szeremeta.

The 39-year-old, a future Hall of Famer, looked great in defeat against Alvarez in September 2018, but the following year, he surprisingly struggled with Sergiy Derevyanchenko.

GGG earned the controversial decision in that October fight, a contender for fight of the year. However, the performance left many wondering just how much Golovkin has left. Long considered one of the most devastating punchers in boxing, GGG won an Olympic silver medal at the 2004 games and went on to dominate the 160-pound division.

Despite his status as middleweight titleholder, Murata (16-2, 13 KOs), 35, will be stepping up to the elite level for the first time in his career. He avenged both of his pro defeats via knockout after being outpointed by Hassan N'Dam and Rob Brant.

Since turning pro in 2013, Murata, ESPN's No. 4 middleweight, has never fought less than twice a year. However, his last fight came in December 2019, a fifth-round TKO of Steven Butler.