Amir Khan has backed countryman Kell Brook and his decision to make the step up to fight IBF, WBA, WBC and IBO middleweight champion Gennady Golovkin.

IBF welterweight champion Brook will move up two weight divisions to fight the undefeated Kazakh star in London on September 10.

Khan was unsuccessful in his own bid to step up two weight classes but the Brit expressed his support for Brook, despite the pair's growing rivalry.

"Great work Eddie, preferred to have seen @ChrisEubankJr fight @GGGBoxing with his style but fair play," Khan wrote via his Twitter account.

"Behind you 100 per cent @SpecialKBrook glad you took a leaf out of my book, tough ask but anything can happen, just don't pull out.

"British fighters running the sport of boxing right now, so many fighters willing to fight the best and taking chances."