Floyd Mayweather Jr. says Conor McGregor should "just sign the paper" as talk over a potential superfight bubbled again.
Mayweather, who is unbeaten in 49 professional fights, and Ireland's UFC lightweight champion McGregor have traded verbal barbs for more than a year regarding a potential bout.
Speaking to ESPN, Mayweather -- who is on tour in the United Kingdom -- said: "If Conor McGregor really wants this fight to happen, stop blowing smoke up everybody's ass.
"Sign the paper. Sign the paper. You said you were boss, so just sign the paper and let's make it happen."
Mayweather said he was always asked about making the fight, but at the moment was happy with telling his story, meeting fans and signing autographs as part of his UK tour.
In February, Nevada State Athletic Commission chairman Anthony Marnell confirmed to ESPN that the commission had been made aware of active negotiations between both camps.
McGregor, 28, also successfully applied for a boxing licence in California in December but has never boxed professionally. Mayweather, 40, last fought in September 2015.
Mayweather was at the Savoy Hotel announcing a match between his protege Gervonta Davis, the IBF super featherweight champion, and Britain's Liam Walsh, which will take place in London on May 20.