Wladimir Klitschko has warned Britain’s Anthony Joshua that fighting him will be like “facing Mount Everest” when the two meet on 29 April.
The Ukrainian, 41, who lost his heavyweight title to Tyson Fury in November 2015, will fight Joshua for the IBF, WBA Super and IBO titles.
Klitschko’s defeat by Fury was the Ukrainian’s first loss in 11 years.
“I believe this fight is going to be the most important of my career,” Klitschko told BBC Radio 5 live.
“You can climb Mount Everest in a certain period of time in the window of the year. You might make it or you might not. “But Mount Everest is still there. So am I.” Joshua is the IBF title-holder, while the WBA title was vacated by Fury in October as he sought medical treatment for depression.
Joshua, who visited Klitschko’s training camp in 2014, turned professional in 2013 and is unbeaten after 18 fights.
However, Klitschko would be his toughest opponent to date, with 64 wins and 53 knockouts since he turned pro in 1996.
The fight at Wembley was expected to attract over 90,000 spectators, which would rival the all-time British attendance record set in 1939.