IBF welterweight champion Kell Brook is very familiar with WBC, WBA, IBO, IBF middleweight champion Gennady Golovkin (37-0, 33 KOs).

Last September, Brook moved up by two full weight divisions to challenge Golovkin for the middleweight belts.

Brook was able to hold his own early on, but Golovkin's size and strength provided to be too much for him. Brook suffered a fractured orbital bone and the fight was stopped in the fifth round.

Golovkin has since returned from that fight, and won a tough twelve round decision over Daniel Jacobs in March. It was the first time that Golovkin had gone the twelve round distance and it also snapped Golovkin's 23 fight knockout streak.

In what is likely going to be the biggest fight of the year, Golovkin will defend his titles against Saul "Canelo" Alvarez (49-1-1, 34 KOs) on September 16th. The location and venue have yet to be determined.

Canelo was in action earlier this month, when he jumped from 154 to 164.5-pounds to dominate Mexican rival Julio Cesar Chavez Jr. over twelve rounds at the T-Mobile Arena in Las Vegas. Chavez Jr. had little in the tank after dwindling down to the contract weight and offered almost no resistance in the bout.

At 35-years-old, Golovkin is getting up there in age. Canelo is nine years younger at 26.

Brook believes his former foe is already beyond his best years, but still feels he has too much fire power and aggression for the Mexican superstar.

"I think Canelo is in his prime but Golovkin is not in his prime anymore," Brook told Sky Sports during filming Behind The Ropes. "I think he's still up there [among the world's best], but with the fight against me and Daniel Jacobs I think there's a blueprint that now they've got in their minds that he can be beaten.

"Triple G might be too strong and too much in his face. I can see a Golovkin knockout."