ANTHONY Joshua has said his 13 weeks of preparation has pushed him to a whole new level ahead of his world heavyweight title fight with Wladimir Klitschko at Wembley on Saturday.

The 27-year-old Joshua, who is unbeaten in 18 bouts since turning professional in 2013, said he is not concerned about the punishment he could take in the ring because of his high-intensity training program.

"I've been pushed to places I've never been pushed before," Joshua told the BBC. "I think I take more punishment in the gym than I do in the fights. Sometimes I try things and it doesn't work and I've broken my ribs, my hand, dislocated shoulders in the gym but we get it right for the fight. I've been training under the dark light so I can shine under the bright lights on April 29."

Klitschko, 41, who went unbeaten for 11 years before losing the belts to Tyson Fury in 2015, has 64 wins against four defeats and will be hoping to seize Joshua's IBF crown as well as the vacant WBA and IBO titles.

Joshua expects a tough fight and saying it will be one of the defining fights of his career when he faces the Ukrainian in front of the largest British boxing crowd for nearly 80 years.

"It is one of them. If this was towards the end of my career, I would say: 'This is the defining fight that's going to write the history books,'" the London 2012 Olympics champion added.

"He's coming game, he's coming ready, and the body does what the mind tells it. His mind seems to be in the right place so I'm in for a tough fight."

On the other hand, older brother and former WBC champion Vitali Klitschko is confident his younger sibling will reclaim the titles with a knockout victory.

"The fight is very interesting fight for all of boxing. Two heavyweights. Two Olympic champions. One of them is older than the other one, But I saw my brother in preparation. Nobody is perfect. Everyone has their strengths and weaknesses," Vitali Klitschko said to Sky Sports.

"The weakness of my brother is concentration. Wladimir was not 100 percent focused for the Fury fight. That is why he lost it. He knows that. Right now, he has prepared for this fight so well. I've never seen my brother so focused during preparations."

"And I know Wladimir has great technique, perfect condition, great speed and the main point in life and in sport, great experience and great experience as champion. If Wladimir will be concentrated in the fight, Joshua has no chance. I'm more than sure that in ten rounds - Wladimir will knock Joshua out."