Friday 10 February 2017 19:33, UK
Wladimir Klitschko admits his Wembley Stadium showdown with Anthony Joshua will be the toughest test of his career.
The Ukrainian had been the world's No 1 heavyweight for more than a decade but will be the challenger for Joshua's IBF and the vacant WBA 'Super' titles when they meet on April 29, live on Sky Sports Box Office.
A sell-out crowd at Wembley of 90,000 will dwarf any attendance at Klitschko's previous fights, even during the five years he was unified champion.
It's the toughest challenge I've ever had.
"I had maybe 40,000, 50,000, 60,000 but never 90,000," he told TalkSPORT.
"It's the toughest challenge I've ever had, because in a certain way he is a copy of me size-wise and he is a world champion in a professional sport."
Klitschko believes the similarities between him and Joshua also make it a daunting prospect in the ring, as he looks to become a heavyweight world champion for the third time.
He does not rule out Joshua taking over as the division's dominant force and admits it will be a defining moment for boxing, with so much at stake.
"This fight is definitely something we are thinking is going to be great on both sides," said the 40-year-old.
"One Olympic champion is fighting another one, one generation is fighting another generation, so there are a lot of questions.
"Do I still have it? Is Anthony good enough now? All these questions are in our minds. But we never thought it was going to be that big.
"Thankfully, it is that big, and it's getting even bigger, unexpectedly it's getting even bigger, and the interest is tremendous and amazing."
Watch Anthony Joshua vs Wladimir Klitschko live from Wembley Stadium, on Saturday, April 29, live on Sky Sports Box Office.
