Raymond Daniels will face Rafael Aghayev in the main event of Karate Combat 37 at Universal Studios in Florida on December 17.
Daniels, you'll remember, made his successful debut against Franklin Mina back in August at Karate Combat 35.
He holds notable wins over Stephen 'Wonderboy' Thompson and Michael 'Venom' Page.
Agyhaev, meanwhile, is widely considered to be the greatest karateka of all time.
However he will have it all to prove against Daniels with the vacant interim welterweight championship up for grabs.
Daniels, 40, declared: “He’s only competed in his own discipline.
"He’s been the best at it, but he’s never stepped outside his own world.
"You can be the biggest dog in your own pound but when you finally step outside you realize it’s a big world out there and there's a lot of big dogs.
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Raymond Daniels vs Rafael Aghayev has been confirmed as the main event of Karate Combat 37
“I don't want to hurt anyone’s feelings, but I am the greatest and I'm willing to put my name versus his name. If he wants people to continue calling him the greatest, he shouldn’t fight me. Fighting somebody of my caliber is a big risk for him.”
Olympic silver medallist Aghayev added: "I don't like to talk too much, I do my talking in the fight.
"All I will say is that I have won many titles and championships in my career and I am not finished yet.
"As long as I am alive, I want to be No.1 in whatever I am doing. I respect all my opponents, no matter what they say. I treat everyone with respect, because first and foremost I have respect for myself.
"I am always pleased when people describe me as the best ever, but there are no tricks or secrets in my success - it's all because of hard work and hard training. I am still working as hard as ever and I am still fully focused on being No.1. I look forward to meeting Raymond Daniels in December."
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Adam Kovacs, Karate Combat president, continued: “This is one of those all-time wishlist fights in our sport, on par with Mayweather vs Pacquiao.
"Rafael Aghayev is the best competitor of all time in Olympic karate and Raymond Daniels holds the same status across a variety of disciplines.
"Nobody was ever able to make this fight happen - until now.”
The event will be the third straight time that Karate Combat has held a card at Universal Studios.
Karate Combat 37 fight card (confirmed bouts)
Raymond Daniels vs Rafael Aghayev - for vacant interim welterweight championship
Eoghan Chelmiah (c) vs Jesus Lopez - for bantamweight world championship
Samuel Ericsson vs Tarek Khelfi - lightweight bout
Good news, fight fans! Karate Combat 37 will be shown free-to-air on YouTube in the UK, with tickets available to purchase via www.karate.com/tickets.