Last month, IBF, IBO, WBA heavyweight champion Anthony Joshua said he was ready to "rock and roll" with Tyson Fury whenever the former champion wants to get in the ring with him.
Fury has not fought since taking four belts from Wladimir Klitschko in September 2015, but, with his well-publicised problems with UK Anti-Doping now behind him, the 29-year-old has returned to training.
The Manchester-born fighter still needs the British Boxing Board of Control to return his professional licence, but he has spent the last week telling Joshua, in several interviews and on social media, that he will be back soon to retake the titles he was forced to give up.
Not that the 28-year-old Joshua has been paying much attention as he prepares for his next fight at the end of March, most likely against WBO champion Joseph Parker.
Joshua, who beat Klitschko in arguably the fight of the year at Wembley in March, believes Fury would be better served by "working his way back" over the next two years, but, if the self-styled 'Gypsy King' is in a hurry, so be it.
"If he wants to get straight in the ring with me in the summer, let's rock and roll," the London 2012 Olympic champion said.
"The ball is in his court but either way I'm ready to roll - I don't mind what we do."
Fury has taken to social media to answer the call, daring Joshua to fight him in his first bout in over two and a half years.
"As a sporting challenge I lay down the challenge for Anthony Joshua to fight me in my first fight back in over 2.5 years," Fury wrote on Twitter.
"I'm the best heavyweight on the planet, come prove I'm not? The ball is in your court don't let your fans down CHAMP. I'm that good I don't need any warm ups I can come off the couch and beat up on Anthony Joshua don't run your big a*** in the bush, let's fight this summer!"