Floyd Mayweather knew protege Gervonta Davis was special when he asked for a selfie as a fan

Floyd Mayweather Jr claims he knew IBF super-featherweight champ Gervonta Davis was special from the first moment he met him.

The unbeaten Davis, who is America's youngest world champion at 22, makes his first defence against Cromer's Liam Walsh at London's Copper Box Arena on Saturday night and Mayweather says his protege is special.

Davis asked Mayweather for a selfie during his promotional tour for his fight against Saul 'Canelo' Alvarez in 2013 and knew from the buzz around him that he had to sign this exciting talent.

"I'm just thinking back to how everything played out and how we came together," said the ring legend.

"I can remember a kid came up to me when I was on the press tour for the Canelo fight and he wanted to take a picture with me.

"We took a photo and when I looked at him I thought there was something about that kid that made him look special.

"Some other people who were in the audience said he's the next big thing.

"I kept hearing the name Tank, Tank, which is his nickname. So he came to my gym and boxed another fighter in my gym and I felt he had a special look about him.

"I got in touch with him through social media and said to him that whatever it would take to get you to the next level, let's make it happen.

"We met and I told him that in 24 months, if he listened to me and continued to work hard, he would be world champion. He's done that, but that's just the first stepping stone."

Mayweather respects the challenge posed by Walsh, who is also undefeated with a 21-0 record.

"Right now in boxing, Tank is the only fighter facing back-to-back undefeated fighters," said the American. "He's just faced an undefeated world champion and now he's fighting his mandatory, who's also undefeated.

"I'd like to commend Liam Walsh and Frank Warren for stepping up to the plate and making this fight happen."