YouTuber-turned-boxer Jake Paul has been accused of refusing drug testing by the father of his next opponent, Tommy Fury ? the brother of WBC heavyweight champion Tyson.
The unbeaten novices are set to meet in Tampa on December 18, in a main event titled 'One Will Fall'.
Preparations have been marked by Paul making bizarre demands of Fury such as changing his name to 'Tommy Fumbles' if he loses, and the 4-0 Ohio native now stands accused of dodging drug testing.
The 7-0 Mancunian's charismatic father, John, has claimed that there is "all kinds of stuff in the contract" for the clash.
"You've got to do this and you've got to do that," he added to interviewer Rob Moore.
"I could go into it more and more but I don't want to bore people with the politics.
"They wouldn't sign up to the VADA [Voluntary Anti-Doping Association] testing as well."
"That bothered me a little bit because I wanted that in the contract, but they wouldn't do that. I'm not even bothered about that... what they're going to do, they're going to do anyway.
"We just want the fight because we know we can win it. People think that Tommy's getting paid to lose, they're joking. A Fury would rather be put do death than go down that road."
Paul is said to have last taken part in drug testing when he beat ex-UFC welterweight champion Tyron Woodley by a controversial decision.
As the August bout took place in his home state, however, this was done on the behalf of the Ohio Athletic Commission and not VADA.
In the run-up to the bout, Woodley accused Paul of taking steroids, which he denied, and claimed he was never tested by the Ohio body.
Paul's camp has also declined to comment to The Mirror on the accusations coming from the Fury camp, with regards to their alleged reluctance to tow the line this time round.
Ex-welterweight champion Paulie Malignaggi believes that Paul could be in trouble.
"I'm actually hearing a lot of people in the US picking Tommy Fury," Malignaggi told Boxing Social.
"He's got an ace up his sleeve: he's got his brother, Tyson. I've seen some videos and stuff. He's helping him train and he's involved in camp.
"Jake has a lot to work on, so does Tommy. But I think Tommy has a big motivation in having Tyson with him.
"Jake doesn't have any dummies around him, either. [Former cruiserweight title holder] BJ Flores is a smart guy; he'll have him ready as well. But I think it's a legitimate 50/50 fight.
"I wouldn't consider it Jake fighting a boxer. It's Jake the reality star turned boxer versus Tommy the reality star turned boxer. That's all it is - am I wrong?"
John Fury is in no doubt about what will happen. "I'm looking at Tommy winning light-heavyweight titles," he said, insisting that the bout with Paul is not risky.
"If you can't beat the Jake Pauls of the world - the kid's a limited kid, we know this.
"He probably wouldn't win a decent-level amateur contest. He's never fought a real boxer, they're all YouTubers and MMA guys.
"I'm expecting Tommy to knock him spark out in four rounds. Jake Paul will quit; I expect him to quit under immense pressure."
Paul had not publicly responded to the allegations made by Fury senior on Monday. Mirror Fighting said it had contacted his representative for comment.