George Kambosos and Devin Haney will fight for the undisputed lightweight title in Melbourne on 5 June.
Australian Kambosos claimed the WBA (Super), IBF, WBO and The Ring belts with a stunning victory over Teofimo Lopez in November.
Kambosos was in talks to fight Vasiliy Lomachenko, but the Ukrainian has stayed in his home country to defend it against the Russian invasion.
The bout with American Haney will take place at Docklands Stadium.
“There were only two names I ever asked for for this fight: Lomachenko and Devin Haney,” said 28-year-old Kambosos.
“Unfortunately, Lomachenko’s not available. Beautiful – Devin Haney, step up, now we’ll take your belt.”
Haney, 23, has defended the WBC belt four times since winning it in 2019.
He holds a 27-0 record, while Kambosos is 20-0.
“I’m so grateful for this opportunity, I can’t wait,” Haney said. “There will finally be a king of the division.”
The regular WBA lightweight title – held by Gervonta Davis – is a lesser belt than the Super title, meaning all four major titles will be on the line when Kambosos meets Haney.
