Hall of Fame boxers Wladimir and Vitali Klitschko are preparing for the biggest fight of their lives -- the Ukrainian brothers are vowing to defend their country from the Russian attacks.
Wladimir spoke out about the invasion of his country on Thursday ... condemning Putin's actions and pledging to join in the fight with the Ukrainian people against the Russian regime.
"I am writing to you from Kyiv, the capital of a country at war, a country being attacked and invaded from all sides," the former heavyweight champ said.