Floyd Mayweather calls out Conor McGregor over a prospective fight

Floyd Mayweather has not been in a ring since September 2015

Floyd Mayweather has urged Conor McGregor to get the ball rolling on negotiations over a potential fight.

Speculation has been growing that the retired former pound-for-pound king was "very, very close" to agreeing to a super-fight with UFC lightweight champion McGregor.

'Notorious' applied last year for a licence to box in California and last week fuelled talk of a showdown with five-weight champion Mayweather by posting a video of himself sparring on Instagram.

On Tuesday night, Mayweather poured cold water on reports that a deal had been agreed, with McGregor responding later by tweeting a picture of himself on a throne saying: "I am in Las Vegas. Floyd has retired on my arrival."

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Conor McGregor has posted a sparring video on Instagram

However, by Wednesday morning Mayweather was back on Twitter again and said: "Listen, Conor McGregor, if you really want to get this fight done…take care of your business with the UFC and then have your people get in touch with my people."

Last month, Mayweather exclusively told Sky Sports that a fight against McGregor was the only one which could get him to come out of retirement.

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Stories have gathered momentum over the last few days concerning the potential showdown between the 39-year-old American and Irishman McGregor, who is more used to fighting in an MMA octagon, but has expressed a desire to test his punching power inside a ring.

Rumours have also gained credibility with the Nevada State Athletic Commission chairman, Anthony Marnell, revealing that talks between the two fighters had taken place.

Mayweather, who retired after defeating Andre Berto in September 2015 to match Rocky Marciano's perfect 49-0 record, kick-started this latest exchange on social media on Tuesday by giving his thoughts on the latest reports.

"Although there has been several rumours circulating thru [sic] media suggesting that I will have an upcoming fight, I'd like to set that record straight and state that there has been no deals made on my behalf in regards to a bout with any fighter at this time," Mayweather tweeted.

"I am happily retired and enjoying my life! Rest assured that if any changes come about, I will be the first to let the world know!"