The 25-year-old Joshua, an Olympic gold medallist, has knocked out all 12 of his professional opponents inside three rounds to date and is favourite to preserve his unbeaten record when he faces the experienced ‘Kingpin.’
Johnson, 35, has never been stopped and went the distance with Vitali Klitschko in 2009. He is seen as a clear step up in class for Joshua but is adamant he can go one better than providing a stern test by defeating the home fighter.
He said of Joshua: “He is a media hype job and let me tell you this, once this dude is out the way I???m going to show you that the future of the heavyweight division is right here.
“I???ve said it before, I???ve got the antidote for this guy. It???s something all of these amateur Olympic guys have in them, you???ll see come Saturday – that???s all I???m going to say on that.
“I???ve been here for two months now and not remotely homesick – I???m hungry for something, and I know what I???m about to get.
“My training has been in a highly classified location, we been keeping everything under wraps and under the hat, so nobody know about that. We don???t want to be scaring people off.
“I???ve been ready for two weeks. Let me tell you this ??? I???ve been a pro since 2003, this is the best shape and condition I???ve ever been in during my whole career.
“For the last two years I didn???t even train and I didn???t even care. The days of hurting my career are over. I blew it by not training and just turning up – but not for this, not for this right here!
“I???m going to give the fans exactly what they deserve, something I???ve had deep down inside of me. It???s taken for someone over here in the UK to bring that out of me. I???m not going to complain.
“Let me tell you how real it is ??? this preparation tops Vitali Klitschko preparation – that guy was then the biggest in the world. That was supposed to be your biggest preparation right there. For Vitali I was 60 per cent, this I???m 100 per cent so I don???t know what else to say. I???m really afraid of myself to be at this point right here, I???m going to be explosive.”
A thrilling night of boxing in London includes Kell Brook, Kevin Mitchell and Lee Selby in world title fights in addition to Johnson’s chance to make good his threats.