The former world heavyweight champion is protecting his homeland on the front line against the Russian invasion and Wladimir says it is a far more important fight than any during his glittering boxing career.

The 45-year-old star told the Daily Mirror newspaper: "Boxing is sport – this is war, and our people are dying.

"During this conversation with you, innocent women, children and civilians will be subjected to bombs, missiles and horrifying reality of war. People say this is the biggest fight of my life, and I agree – it's so sad to realise how terrifying the war is."

Russia have been isolated in the world of sport following the invasion and Klitschko believes it is "crucially important" as it will make people question the actions of the country's leader, President Vladimir Putin.

He said: "To isolate Russia from all sporting competition is not an act of aggression. We do this to stop the war, in the name of peace. I have nothing personal against the athletes, but I have a lot against the aggression of Russian leader Putin.

"We believe sanctions on different levels, including sport, are crucially important.

"If you take away sporting competition the athletes will ask their leader, 'Why will nobody compete against us?' I repeat, this is not against the athletes, it's in the name of peace in Ukraine."

Klitschko has urged people to do whatever they can to support Ukraine.

He said: "Let me tell you the reality of war – while you are talking to me now, Ukrainian women and children are dying at the hands of Russian aggression.

"Innocent civilians are being forced from their homes. Our military personnel are defending the honour of an independent and free Ukraine.

"It's important to act now in any way possible. Don't wait for a few weeks, don't delay because every single minute, every hour of every day counts."