Wladimir Klitschko and Alexander Povetkin fight set for October
WBA heavyweight champion Wladimir Klitschko will face Alexander Povetkin in Moscow on 5 October.
Klitschko was first set to defend his heavyweight title against the Russian three years ago but the contract for the fight was never finalised.
"We could have met earlier," Klitschko said. "He hasn't lost a fight and in no case will I underestimate him."
Povetkin said: "I'm glad it will finally happen. I'm looking forward to meeting the strongest boxer right now."
The WBA heavyweight belt became vacant when Ukrainian Klitschko was elevated to "super champion" status in 2011 after beating David Haye.
Povetkin, 33, beat Ruslan Chagaev to claim the vacant title later in 2011, before victory over American Hasim Rahman last September saw him become the mandatory challenger to Klitschko.
Klitschko, 37, improved his career record to 60-3 earlier this year when he defeated Francesco Pianeta with his 52nd knockout.
The undefeated Povetkin's record stands at 26-0, with his 18th knockout stopping Polish challenger Andrzej Wawrzyk for his fourth successful defence of the "regular" title.
Moscow's indoor Olympic stadium is scheduled to be the venue for the bout.