Floyd Mayweather has insisted he is "officially coming out of retirement" to fight Conor McGregor.
Mayweather urged MMA star McGregor to stop "crying" about money and sign terms with his UFC bosses, so the pair can meet in a cross-codes fight this summer.
The five-weight world champion told fans he was tired of hearing excuses from McGregor when he appeared at Liverpool's Auditorium on his latest leg of his UK Undefeated Tour on Friday night.
"When I faced Arturo Gatti, I went to his turf and he was the A-side I was the B-side," said Mayweather. "I beat him and I didn't cry or I didn't complain.
"Oscar De La Hoya, he was the A-side, I was the B-side. I didn't cry, I didn't complain. I beat him and I became the A-side.
"Now Conor McGregor, I'm officially coming out of retirement just to fight Conor McGregor. I don't wanna hear any more excuses about the money.
"Sign the paperwork with the UFC so you can fight me in June, simple and plain. Let's fight in June. You're the B-Side, I'm the A-side.
"I'm tired of all this crying about money and blowing smoke up everybody's a**. If you want to fight, sign the paperwork and let's do it."