Luke Campbell will take on Vasiliy Lomachenko for the WBC, WBA, WBO and Ring Magazine lightweight world titles at The O2 in London on August 31.
Double Olympic champion Lomachenko, a former WBO featherweight and junior lightweight world title holder, beat mandatory challenger Anthony Crolla during April in Los Angeles, knocking the British fighter out in the fourth round.
Campbell, meanwhile, is ranked number one by the WBC, securing his mandatory world title shot after beating Yvan Mendy at Wembley in September 2018, having previously lost a split decision against Jorge Linares for the WBA crown.
In his last fight, the 31-year-old 2012 Olympic bantamweight champion stopped Mexican Adrian Young in five rounds in Philadelphia during March.
"Lomachenko is ranked number one pound-for-pound on the planet, so for me to fight a guy like that only encourages me more to be the best that I can be and it is exactly the level that I want to be at," Campbell said.
"I'm well aware of how good he is and what he is capable of doing, but I'm also well aware of what I can do and what I'm going to do.
"I think that I can knock out anyone that I hit right, I believe that I am one of the biggest punchers in the lightweight division.
"This is going to be the toughest fight of my life and I'm preparing for it, physically and mentally."
Ukrainian Lomachenko is set to return to London, where he won the 2012 Olympic lightweight gold.
"This is a fight for history because my goal is to unify all of the belts in the lightweight division," Lomachenko said.
"Luke Campbell is the next challenge for me on that journey. He is an excellent fighter who I remember well from the 2012 Olympics. He has a difficult style, and I cannot afford to overlook him."
Promoter Eddie Hearn said: "I truly believe Luke Campbell has a fantastic chance here on home soil to upset his fellow Olympic gold medallist.
"This will be a huge event, not just in Britain, but around the world."