A Russian prankster posing as the U.N. secretary-general managed to reach Poland's president on the telephone and rendered him speechless with questions about Ukraine, Russia and his reelection on Sunday. The prankster, Vladimir Kuznetsov, known as Vovan, posted a recording of the 11-minute call on YouTube. President Andrzej Duda's office confirmed Wednesday that it was authentic. At various points in the conversation, conducted in English, Duda sounds surprised at the line of questioning but still refers to the impostor as “Your Excellency.” Mr Kusnetzov and his partner have previously embarrassed a host of world leaders and celebrities, including Prince Harry, Boris Johnson, Elton John and French President Emmanuel Macron. Mr Duda tweeted on Wednesday that he realized “something was not right” during the conversation, which took place Monday afternoon while the president awaited official word of his election victory. Mr Duda said he was suspicious because the real United Nations chief, Antonio Guterres does not pronounce the name of Polish vodka brand Zubrowka as well as the caller did. But he conceded that the “voice was very similar.” The president ended his tweet with an emoticon of tears of laughter.