'Postman' Anthony Joshua vows to deliver victory over Francis Ngannou
Joshua weighed in at 114.48kg (18st 02lbs) on Thursday with his Cameroonian opponent, a former UFC heavyweight champion, tipping the scales almost two stones heavier.
Ex-Mixed Martial Arts star Ngannou weighed in at 123.64kg (19st 47lbs), just slightly more than when he fought Tyson Fury in October in what was his maiden professional boxing bout.
"Official prediction? I deliver - I am the postman," said 34-year-old Joshua at the weigh-in.
Ngannou, three years older than his British opponent, is the sentimental favourite to win Friday's clash which has been dubbed "Knockout Chaos".
As a child, Ngannou once laboured in a sand quarry for as little as $2 a day before arriving in France where he slept rough in a car park.
Against Fury in October, he sent the world champion crumbling to the canvas in just the third round before losing on a split decision.
"I have learnt a little bit from the last fight, the last camp, and leading up to this one, so I get a little bit of experience, but the mindset is still the same," he said.
"This is just my second boxing match, even though I am taking on the two best guys in the world in boxing.
"I am the underdog, I am going out there to prove that you can be an underdog and stand your ground."
The winner of Friday's contest is expected to be in line to at some stage face either Fury or Oleksandr Usyk, who will fight for the undisputed heavyweight title on May 18th in Saudi Arabia.
"Sometimes it just makes me laugh a little bit, because we are going to fight in boxing rules, but what would happen if it was a 'free' fight under MMA rules?" added Ngannou.
"I would smoke this guy. I am the only one to go in their backyard, none of them can come in my backyard. I would take two of them at once."
