Eddie Hearn claims he 'nearly fell out of his chair' when he found out about Tom Aspinall's UFC purses.
Aspinall teamed up with Hearn in a commercial and advisory deal following the launch of Matchroom Talent Agency.
The 46-year-old boxing promoter described his role as Aspinall's 'manager', with the UFC heavyweight champion still signed with Dana White and the UFC.
The Matchroom chief, who has been involved in a war of words with White following Zuffa Boxing's blockbuster signing of Conor Benn, will be tasked with building Aspinall's commercial brand outside of the Octagon.
He will also aim to maximise the 32-year-old's UFC contracts.
And after going through the Briton's purses, Hearn was left shocked at how little his newest client was getting paid by the MMA leaders.
Eddie Hearn signed Tom Aspinall to Matchroom Talent Agency. Image: Getty Speaking in a media scrum at Friday's launch press conference via Aspinall's YouTube channel, Hearn exclaimed: "When I talked through Tom Aspinall's purses, I nearly fell off the f**king chair because I know if that was our business, he'd be making 10X as much money. His return is gonna be massive.
"As an organisation, they need him," he added. "Forget he needs the UFC. He actually don't need the UFC now, but they need him because they need heavyweight stars."
Given Benn's high-profile split with Hearn and the details surrounding his lucrative one-fight deal, Aspinall was asked about his fellow countryman's contract.
"I think if one guy gets $15m and the other guy gets $15k, that's a big deal to make, which is part of the reason I want to explore other options," he said.
"I want to be a trailblazer for MMA fighters who can make a lot of money and be successful outside the octagon as well as inside.
"Publicly or privately, a lot of MMA fighters complain about the money we're getting paid, but that's the contract we all signed. I've accepted that and I want to make as much money outside the octagon as I possibly can."
What has Dana White said about Tom Aspinall linking up with Eddie Hearn?
The rivalry between Hearn and White escalated when the latter signed Benn to his Zuffa Boxing stable.
Hearn has returned fire by recruiting Aspinall to his new agency company and the UFC boss was asked about the stunning link-up.
Tom Aspinall's UFC heavyweight title fight against Ciryl Gane ended in a no contest after he was poked in the eye. Image: Getty Speaking at the UFC 326 pre-fight press conference, White said: "We don’t have any issues with Eddie. They can get whoever they want to represent them - Tito Ortiz used to represent people and we got it done!"
Aspinall is currently sidelined with an eye injury after suffering a nasty double eye-poke in his fight against Ciryl Gane at UFC 321 last October.
He'll have Hearn in his proverbial corner when he makes his UFC return.