British heavyweights Tyson Fury and Dillian Whyte both say they are prepared to fight each other.
Last week the World Boxing Council (WBC) ordered Fury and Whyte to fight a final eliminator for the right to face American WBC champion Deontay Wilder.
In an Instagram video, Fury, 30, said: “I accept the challenge. I’ll fight Dillian Whyte every day of the week.”
Whyte, 31, responded on Twitter by saying: “Let’s do it then. I’d fight you anytime, anywhere.”
Fury, who is scheduled to fight American Tom Schwarz in Las Vegas on 15 June, fought out a controversial draw with Wilder in December, with many pundits believing the Englishman deserved the win, despite being knocked down twice.
A rematch had been expected to take place this year but fell through, with Wilder now facing fellow American Dominic Breazeale in New York on Saturday.
But the WBC said Wilder’s next fight after this weekend should be against either unbeaten Fury or Whyte, who has only lost once in 26 fights – a seventh-round stoppage loss to Anthony Joshua in December 2015.
“I just want to say a special message to the WBC, who supported me in my comeback and been very fair with me over the years,” said Fury.
“I recently saw your quote about fighting for the interim title against Dillian Whyte and I’m very thankful for the opportunity.
“But what I suggest is, because I beat Deontay Wilder and we all know what happened, I didn’t get the decision, but I still won and the world knows.
“I propose we make me and Dillian Whyte for the WBC ‘diamond’ belt and not the interim belt. Make it for the diamond belt not the interim version and you’ve got a deal. I’ll take care of Dillian Whyte and I’ll knock him out within six rounds.”
Whyte is currently scheduled to fight Colombia’s Oscar Rivas in London on 20 July but that fight could be cancelled if a bout with Fury was agreed.
The diamond championship belt was created by the WBC in 2009 and is an honorary championship fought for in what the council decides is a historic fight between two high-profile and elite boxers.