Vasiliy Lomachenko will fight fellow world lightweight champion Teofimo Lopez on October 17 in Las Vegas to decide the division's No 1 fighter.
The brilliant Ukrainian Lomachenko holds the WBA, WBC 'franchise' and WBO titles while undefeated Lopez is the IBF champion.
Lomachenko vs Lopez has twice been postponed this year already due to the coronavirus pandemic but both fighters remained committed to getting a third deal over the line.
Lomachenko said: "Lopez can talk all he wants. He's very good at talking. He has done nothing but say my name for the past two years. I am a fighter, and my goal is to win another world title. Good for Teofimo. When we fight in Las Vegas, he will eat my punches and his words. I will be the better man, and four world titles will come home with me to Ukraine."
Egis Klimas, Lomachenko's manager, said: "Nobody has seen Lomachenko at 100 per cent inside the ring. If Teofimo can push Loma to at least 80 per cent, it means Teofimo is the best opponent Loma has faced."
Lopez said: "I will beat up Lomachenko and take his belts. Simple as that. I'm coming to Las Vegas to make history. I don't like the guy, and I'm going to have fun as Lomachenko's face is beaten and marked up by my hands. The Takeover is here, and the reign of Lomachenko, the little diva, is coming to an end."
New-York based Lopez is nine years younger than Lomachenko but represents an intriguing new challenge.
Lopez won his first world title in his most recent fight, by stopping Richard Commey, and has immediately jumped at the opportunity to face the pound-for-pound phenom Lomachenko.
He has developed a reputation as a dangerous puncher with 12 stoppages in his 15 wins.
But Lomachenko is a huge step up for Lopez - the Ukrainian is a two-time Olympic gold medallist and the fastest-ever three-weight world champion, achieving the feat in just 12 fights.
If he beats Lopez he will have won every major title at lightweight.
Lomachenko vs Lopez is part of an exciting division that also includes Britain's Luke Campbell aiming to finalise a fight against US prospect Ryan Garcia for the WBC 'interim' belt.
Devin Haney, another undefeated talent from the US, holds the full WBC title.
Top Rank promoter Bob Arum said: "Teofimo and Vasiliy demanded the fight, and we are glad we could make it happen. Vasiliy has never backed down from a challenge since he turned pro under the Top Rank banner, and Teofimo is a fearless young champion daring to be great. This has all the makings of a modern boxing classic."
Beterbiev finally fights in Russia
Artur Beterbiev will defend the IBF and WBC light-heavyweight titles against Adam Deines in Moscow on October 23.
It will be Beterbiev's first fight as a professional in his home country of Russia.
Beterbiev is the only world champion with a 100 percent knockout ratio - he most recently stopped the previously-unbeaten Oleksandr Gvozdyk.
"He is a complete, absolute beast! Anything in front of him, he takes down," Top Rank president Todd DuBoef told Sky Sports.
Inoue makes Vegas debut
'Monster' Naoya Inoue will defend the IBF and WBA bantamweight titles against Jason Moloney in Las Vegas on October 31.
DuBoef told Sky Sports about Inoue: "He has this telegenic style. Boxing enthusiasts have a great appreciation for Inoue so we wanted to bring him to America to get him more exposure.
"In essence, he is like Manny Pacquiao, a kid from Asia with dynamite in both hands."