Wladimir Klitschko has told Anthony Joshua he will be facing Mount Everest when they fight at Wembley Stadium on April 29.

The 41-year-old Ukrainian is bidding to win Joshua’s IBF heavyweight title and the WBA belt last held by Tyson Fury in front of what is expected to be a record crowd of 90,000 for a boxing event in the London.

Klitschko took to Twitter to mock Joshua’s claims on Tuesday that he “needs to be a billionaire”, and the former WBO, WBA, IBF and IBO champion has now aimed a swipe in the Englishman’s direction.

On April 29th I'm going to fight a wannabe billionaire. Fellas, how many wannabe billionaires did you "fight" in your life? I've none.

— Klitschko (@Klitschko) April 8, 2017

Klitschko will stand as Joshua’s biggest challenge in his career to date, in which he has so far fought 18 times, with 18 knockouts.

Meanwhile, Klitschko’s only defeat in 11 years came against Joshua’s compatriot Fury, a vastly different fighter. The Ukrainian dismissed suggestions he is in decline, comparing his exceptional longevity with the world’s highest peak, and the scale of the task Joshua has to overcome.

“Please excuse me and this may sound arrogant, but for example, a parallel: Mount Everest, the highest mountain in the world,” Klitschko said.

“It’s there. It’s been there for a long time and will be there for a long time. You can climb it during a certain period of time: during two weeks in April I believe.

“You can get to the top and say ‘I conquered Everest’. Then you’ve got to run down because it’s going to take you down if you miss the time.

“After you’re down, a lot of people died there. Some made it, not many, but some made it back. But Mount Everest is still there. Is Mount Everest defeated? It’s still there and it’s going to take another life this April.