Kell Brook spoke of the 'fear factor' involved in next month's showdown against WBC, IBO, WBA and IBF middleweight champion Gennady Golovkin.

The 30-year-old steps up from welterweight to challenge a fighter widely compared to Mike Tyson and on the brink of establishing himself among the finest middleweights in history.

Brook is already considered a major underdog for their September 10 clash at London's 02 Arena, but the Sheffield fighter remains adamant that the risks involved will inspire his greatest performance.

The undefeated IBF welterweight champion has often underperformed when over-confident, notably doing so against Carson Jones in 2012, but he is looking forward to seeing how he fares against one of boxing's elite.

Brook's previous struggles to make the welterweight limit were no secret. He has often appeared to be at least a natural light-middleweight battling to remain at 147lbs.

The powerful Golovkin, meanwhile, remains the world's most intimidating fighter through his record of stopping 32 of his 35 professional opponents.

He has also only been taken to 11 rounds once, and on that occasion against Martin Murray it is arguable the Briton should have been withdrawn earlier.

Brook became his opponent after what Golovkin's promoter Tom Loeffler described as "frustrating" negotiations surrounding Chris Eubank Jnr. The Kazakh, however, insisted Brook cannot be underestimated because of the numerous occasions smaller men have defeated some of the sport's greatest names.

"This is the biggest test for me," said the 34-year-old, whose trainer Abel Sanchez oversaw Jones' fight with Brook. "Kell's coming to the middleweight division.

"I remember fighters in history, Sugar Ray Robinson, Sugar Ray Leonard, (Antonio) Margarito, (Oscar) De La Hoya. Everybody has problems (against smaller opponents), because of different speed, different timing, different power.

"I am very excited. I am very happy to be here in London. Right now, I can give the UK fans an amazing event. I believe this is the biggest fight for us because I see Kell [and] I respect him. I respect his team, he has a very good and very strong team.

"I understand this is not easy, this is true. It is very serious business for us. I am ready 100 percent for September 10.

"I believe I will bring an amazing show, like a drama show. This is the biggest test for me because Kell is a true champion. It's the biggest test for me, absolutely."