“If Conor McGregor really wants this fight to happen, stop blowing smoke up everybody’s ass,” Mayweather told ESPN, accusing the Irishman of stalling on a deal.

“Sign the paper. Sign the paper. You said you were boss, so just sign the paper and let’s make it happen.”

Speculation of a fight between retired former boxing welterweight king Mayweather and McGregor has intensified in recent months.

In February, a report in Ireland said the two sides had agreed terms and were only awaiting the resolution of a “third party hold-up” to confirm the deal.

The Nevada State Athletic Commission also confirmed it was aware of negotiations between Mayweather and McGregor.

Mayweather, who retired undefeated in September 2015 with a perfect 49-0 record, has said he is willing to fight McGregor in a boxing ring.

However McGregor, 28, is under contract to the Ultimate Fighting Championship, who would have to sign off on the bout for it to happen.