Promoter Eddie Hearn said last week that the bout between the pair is "as done as it can be".
Fury is confident he can finish the contest - which is likely to occur in late July or early August - within the first nine minutes and has volunteered to retire on his stool if Joshua hears the bell for the fourth round.
"While I'm on a rant I may as well call out one more person: a big, useless dosser, not a real fighting man, a hype job, bodybuild, cross-fit, big, ugly s***house, that's Anthony Joshua," Fury said in a video message on Twitter.
"AJ, if you're out there, let's make this fight happen you big dosser. You big s***house bum dosser, I'll smash your face in and there's not one thing you can do about it. Prove me wrong, sucker, prove me wrong, I'm number one.
"If you go past three rounds with me, I'll quit in the corner because that's how confident I'm taking you cold out within the first two or three rounds. Out like a light switch."
Watch: Eddie Hearn talks Canelo-Saunders, Fury-Joshua, Triller and more