Tyson Fury and Dillian Whyte insist they are willing to fight later this year.
Last week, Fury shot down a potential eliminator against Whyte, but now he's changed his mind.
The World Boxing Council last week ordered they fight in a final eliminator to challenge WBC heavyweight champion Deontay Wilder, who Fury controversially drew with in December.
Fury will fight for the first time in Las Vegas against Tom Schwarz on June 1, a month before Whyte fights Oscar Rivas in London, on July 20. And Wilder is back on Saturday, when he faces mandatory challenger Dominic Breazeale at Barclays Center in Brooklyn, New York.
Speaking in a video on social media, the 30-year-old Fury said: "I accept the challenge. I'll fight Dillian Whyte every day of the week."
Whyte responded by writing: "Let's do it then. I'd fight you anytime, anywhere."
The 31-year-old Whyte also remains in contention for a rematch with Anthony Joshua, his long-term rival.
However, Fury said he was only willing to face Whyte if the WBC sanctioned the bout for their "Diamond title."
"I recently saw your quote about fighting for the interim title against Dillian Whyte and I’m very thankful for the opportunity," Fury said on Instagram.
"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 that we make me and Dillian Whyte for the WBC 'diamond' belt and not the interim belt.
"I’ll take care of Dillian Whyte and I’ll knock him out within six rounds. I accept the challenge, thank you very much. I’ll fight Dillian Whyte every day of the week and twice on a Sunday, WBC. Make it for the diamond belt and not the interim version and you’ve got a deal. Let's get it on!"