Former five-weight world champion Floyd Mayweather Jnr has urged middleweight king Gennady Golovkin to step up in weight to prove his class.

The Kazakh is currently in training for his next bout after securing a fifth-round stoppage over Britain’s Kell Brook last month.

Golovkin has now made 16 defences of his WBA middleweight strap and two of his IBF title and many are claiming he is the pound-for-pound best at the minute.

Mayweather has been linked with a fight with GGG in the past but the American is enjoying life as a retired fighter and is working as a promoter at the minute.

Golovkin will take on mandatory challenger Daniel Jacobs in his next fight, but he still wants to take on Saul ‘Canelo’ Alvarez in 2017.

Despite the hype, Mayweather believes the 34-year-old needs to start moving through the weights before he can join the world’s greatest.

He told reporters in Las Vegas, according to World Boxing Scene: “What we want to see is this: we’ve seen Sugar Ray Leonard go up in weight, Roberto Duran go up in weight, we’ve had so many legendary fighters go up in weight but my nephew’s favourite fighter, Triple G, has yet to go up in weight.

“I see my nephew after the Kell Brook and he said [Golovkin] ‘wasn’t what I thought he was, he cool’. I told you he’s got punching power for a stationary target.

Then he said ‘unc, you would have stopped him, you would’ve destroyed him’. I said ‘nephew you ain’t telling me nothing new’. He was just a fan of Triple G fighting those stationary targets.”