Daniel Dubois has already faced Anthony Joshua before ahead of their big British fight - and left quite the mark.
When the two boxers meet on September 21 at Wembley, there will surely be fireworks with two of the biggest heavyweights around currently.
But it will not be the first time and they famously sparred in 2016 when Triple D was just a teenager - leaving AJ on the deck.
Dubois was just about to turn professional and was already making a name for himself as the freakishly huge knockout artist and the next big thing in British heavyweight boxing.
Anthony Joshua and Daniel Dubois have met before - with interesting results
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Joshua had, ironically, just become the IBF heavyweight champion after defeating Charles Martin while former boxer Anthony Fowler recounted the time they met in the gym.
Speaking to talkSPORT, Fowler said: "They were just sparring normally. Dubois was really young so he wasn't really trying to win the rounds.
"I wouldn't say he was in survival mode but he wouldn't take many risks.
"He was very cagey sparring Joshua. Obviously, Joshua was the main man on the team so he was always quite wary, but he always punched really hard.
"I remember he hit Frazer Clarke so hard that he snapped his ankle.
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"He fell to the floor and snapped his ankle. After that, he was walking around with a cast so he's always had that real power Dubois.
"Joshua must have been a little clumsy sparring him and he got caught with a short left hook and Joshua's legs completely went.
"Dubois could have hit him again and put him to sleep but Dubois had a bit too much respect for him to finish him off.
"Obviously, everyone was stood there like 'Wow' and Joshua went and jogged around the ring because his legs were like jelly and he was trying to get his legs back.
Anthony Joshua is the slight favourite against Daniel Dubois
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"And everyone was going 'Wait, wait, wait'. Joshua wanted to carry on but Rob McCracken was like 'Have a little break, get your legs back to normal, and then spar' and then they continued sparring.
"He didn't knock him out, he didn't hit the floor but he was really, really hurt.
"Dubois probably could have hit him again and knocked him out but he chose not to out of respect."
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Daniel Dubois can certainly pack a punch though
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There will be no such respect when Dubois and Joshua meet again at Wembley later this month after some trask-talking from both sides throughout the promotional material.
AJ goes into the contest as the slight favourite after returning to form following his double-loss to Oleksandr Usyk.
But Dubois has a frighteningly powerful punch that can knock anyone out if he catches it correctly and, while the 27-year-old also lost to Usyk, his battle was a lot closer.
