By Edward Chaykovsky

IBF welterweight champion Kell Brook was stunned when it was officially announced on Tuesday that his domestic rival Amir Khan was jumping up in weight to challenge WBC middleweight champion Saul "Canelo" Alvarez.

Khan (31-3, 19KOs) has been tagged as a big underdog with weight being the main factor.  The British star will move up by weight pounds to face Canelo at a catch-weight of 155-pounds.

Brook's team was trying to secure Khan for the summer. Brook has a mandatory defense against Kevin Bizier on March 26th. His promoter Eddie Hearn of Matchroom Sport felt the negotiations were going well and anticipated a fight for June 4th at Wembley in London. He was just as surprised when the news broke. 

Brook feels Khan took the fight because he puts himself in a no-lose situation, where he will gain a huge payday and can easily blame the weight in defeat.

Brook told Sky Sports News HQ: "I don't know if he's cashing himself in or what but I don't believe he thinks he can win. That's me being honest. He'll lose in that fight. They can always come back down and fight the welterweights of the world. If he'd got in with me, which we all expected to, I'd definitely end his career.

"Him fighting at middleweight against Canelo, he can always say 'the guy was too big for me. I thought this and I thought that.' He can come up with that and drop back down so it's win-win for Khan I think.

"It's always going to be on the table. It's a good move he's done. With the demand we still have to sit down and talk. As much as I'd like to say 'get lost', with the demand from fans all over the world, they'll still want to see that fight."