LONDON - British boxer Kell Brook promises to "shock the world" when the IBF welterweight champion jumps two weight classes to fight middleweight champion Gennady Golovkin. The Sept. 10 fight is at the 02 Arena in London.

"I always seem to do enough, and I always find a way to win ... I'm going to shock the world," the 30-year-old Brook said Monday at a news conference in London with Golovkin. "You're going to see the best of me, I'm at my natural weight."

"I understand it's not easy, it's the biggest test for me, absolutely," said the 34-year-old Kazakh.

Both fighters are undefeated. Golovkin is 35-0 with 32 trademark knockouts, while Brook is 36-0 (25 KOs).

Brook is looking full of vitality ahead of his big night and although many are querying the wisdom in the IBF world welterweight king leaping up two divisions to face one of the world's leading pound-for-pound fighters, Ingle is reflecting on a training camp with enthusiasm.

Trainer Dominic Ingle told Sky Sports: "It's been a great camp. Nine weeks has flown - we blinked twice and now it's the week of the big fight. Kell's probably in the best shape he's been in in his life.

"He's keeping his power all the way through the camp. Generally when he comes up to fighting a welterweight, you can feel the power drop as he drops his weight and then you feel it again on fight night when he's carbed-up and has fluid back in him.

"This camp, he's carried it all the way through and into the sparring. He's punching hard, going in with all the tools, the same weight and the same power in my opinion.

"When you see him on the scales on Friday, you'll know the difference. There'll be no fat on him - just muscle. It's proper fighting weight; not something we've just chucked on haphazardly. It's all usable muscle and all usable strength.

"He's got the movement. He's fluid. He's got the footwork and he's been on the lines for years. He's got the footwork and the boxing ability to beat Golovkin."