It seems like the fantasy match-up between boxing legend Floyd Mayweather Jr. and UFC lightweight champion Conor McGregor could take place sometime in late 2017 or early 2018, per fresh reports.

For months, there has been back-and-forth chatter from both men but nothing concrete to suggest that a fight would actually take place. However, on Wednesday, Mayweather appeared on ESPN First Take to throw down the gauntlet to McGregor -- while also declaring his desired terms for the potential super fight.

"You guys keep hearing all these different rumours about different fighters want to face Floyd Mayweather. Everybody keeps talking about Conor McGregor. He's blowing smoke up everybody's a--. Dana White, the UFC --- let's make it (the fight) happen. Bring him over to the boxing world, and I'll show him what it's like," Mayweather said on First Take, via ESPN, while challenging the UFC to close the deal.

Previously, McGregor had demanded a $US100 million ($AU134 million) purse to crossover from the Octagon to the boxing ring to face Mayweather. However, the American countered with a $US15 million ($AU20 million) offer besides a cut of the pay-per-view during his open challenge to the Irish fighter.

Floyd Mayweather Jr. vs Conor McGregor: Irishman offered $US15 million for super fight

According to Mayweather, McGregor hasn't done enough to warrant a higher purse due to his previous earnings with the UFC. "We tried to make the Conor McGregor fight. They know what my number is. My number is a guaranteed $100 million. That was my number.

"We are willing to give him $15 million and then we can talk about splitting the percentage -- the back end -- on the pay-per-view revenue. But of course, we're the 'A side.' How can a guy talk about making 20 or 30 million if he has never made 8 or 9 million in a fight (in the UFC)?"

When grilled about a possible rematch with Manny Pacquiao or a match against the undefeated 'Triple G' Gennady Golovkin, Mayweather reiterated that only a fight with Mayweather would bring him out of retirement. "Only thing I'm probably interested in is the Conor McGregor fight. I'm a businessman, and it makes business sense. I believe in what me and (advisor) Al Haymon talk about every day -- I believe in working smarter, not harder."

Last year, McGregor applied for a boxing license from the California State Athletic Commission and set the rumour bill abuzz. Ever since that move, McGregor and Mayweather have been exchanging harsh words on social media. McGregor, nickname 'The Notorious One', is currently taking time off to be with pregnant partner. The couple is expecting their first child in May.

If reports are to be believed, the Floyd Mayweather Jr. vs Conor McGregor could very well go down in late 2017 or early 2018. Since McGregor is under contract with the UFC, any potential fight with McGregor would need the blessing of the MMA promotion and its president Dana White.