(CNN) -- British challenger Dereck Chisora has risked the wrath of WBC heavyweight champion Vitali Klitschko by slapping his opponent at the weigh-in ahead of their title fight on Saturday.
Underdog Chisora struck Ukrainian Klitschko as the two went face-to-face after they had taken to the scales 24 hours prior to their bout in Munich.
A stunned Klitschko took a step back after Chisora's slap before both fighters' entourages became involved in a brief scuffle.
The 40-year-old, who has a record of 43 wins from 45 fights, vowed to take revenge on Chisora when the two square off in Germany.
"I'll be hitting him back tomorrow, in the ring," Klitschko told reporters.
'"He's not all there. Dereck is full of nervousness and I feel he is afraid, otherwise he would not have jumped back like he did.
"He hit me not like a boxer but like a woman, with an open hand. If he wants to fight properly, he must do that with his fists."
Chisora pulled a similarly controversial stunt when he planted a kiss on Derek Baker before their fight in 2010. He then knocked Baker out in the second round of their bout.
The 28-year-old has twice been scheduled to Klitschko only for the champion to pull out both times with injury. He has won 15 of his 17 professional fights and is a former British heavyweight champion.
Vitali's brother Wladimir currently holds four heavyweight belts and beat another British heavyweight, David Haye, in his last fight.
Wladimir is due to fight former cruiserweight world champion, Jean-Marc Mormeck, from France, on March 3.