In a post that has since been scrubbed from his Twitter account, the official wished his "friend Petro Poroshenko and his future Prime Minister Vovan Lexusov…all the best and victory in Sunday's runoff presidential elections".
Unfortunately, Haradinaj didn't manage to delete the tweet before it was picked up by other users, who took screenshots of the post and spread it far and wide across the internet.
"How are politicians still falling for this?" UK journalist Shaun Walker asked, suggesting that Vovan and Lexus likely called Haradinaj posing as Poroshenko, and were probably likely to release the audio from their latest prank call sometime soon.
Others recalled Vovan and Lexus' other pranking capers, or played along and "congratulated" "Prime Minister Vovan Lexusov".
The tweet proved particularly popular among Serbs, who remain upset over Kosovo's illegal, NATO-backed declaration of independence from Serbia in 2008, with one user saying Kosovo leaders and their apparently poor understanding of international relations provided an "unlimited source of amusement", with another quipping that "Vovan Lexusov" was "more real than the fake prime minister of Kosovo".
Finally, a few speculated about what could have prompted Haradinaj to fall for such an obvious prank, with one user suggesting that perhaps it could be as simple as Haradinaj being lonely and wanting to talk to someone.
British journalist and Eastern Europe specialist Graham Phillips joked about the now deleted tweet, suggesting that Haradinaj could have easily caught on to the fact that he was being trolled "if he had followed the news, at all, over the past few years, or even just googled 'Vovan Lexusov', or even asked one of his assistants perhaps".
Ukrainians are going to the polls on Sunday for the second round of presidential elections, being asked to choose between incumbent President Petro Poroshenko and challenger Volodymyr Zelenskiy.