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LIVERPOOL, England (CBSMiami/AP) — Undefeated boxing champion Floyd Mayweather, Jr. has announced that he’ll step out of retirement to fight the UFC’s Conor McGregor in what’s expected to be one of the most anticipated matches in the history of either sport.

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Mayweather made the announcement in front of a rowdy Liverpool crowd Friday as he traveled Europe on his “Undefeated Tour.”

“I’m coming out of retirement just to fight Conor McGregor,” he said, calling out the Irish mixed martial artist. “I don’t wanna hear no more excuses about the money, about the UFC. Sign the paperwork with the UFC so that you can fight me in June.”

Bookies in Las Vegas aren’t giving McGregor much of a chance should the fight actually happen.

Mayweather is a whopping 25-1 favorite in odds posted recently on the proposed fight at the Westgate Las Vegas Superbook.

“We figure that in a boxing match Mayweather is an enormous favorite,” said Jeff Sherman, an oddsmaker at the Westgate. “It would basically be flipped if it was an MMA match.”

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Mayweather and McGregor have been talking — not to each other — about a possible fight, though both fighters would have to clear a number of hurdles to make it happen.

McGregor has been more vocal about his willingness to fight Mayweather, and has secured a license to box in California. He tweeted in February that he was in Las Vegas and wanted to discuss the fight, and that Mayweather retired upon his arrival. But Mayweather has been retired since beating Andre Berto in September 2015.

McGregor has never fought a boxing match and is under contract to the UFC. UFC president Dana White earlier offered both fighters $25 million for a bout, which Mayweather described as laughable.

The odds posted at the Westgate stipulate that the fight has to happen by May 31, 2018 or that bets will be refunded. It also stipulates the fight would be a boxing match, not a UFC contest.

Bettors would have to wager $250 on Mayweather to win $10. Those who like McGregor can bet him plus 1100, which means that a $10 bet would pay $110.

Sherman said the Westgate would take up to $2,000 on each bet, the normal boxing limit for the book.

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