Ukranian Eurovision Song Contest host Oleksandr Skichko urged competitors to "let it all hang out" during the competition.
But one attendee took his encouragement too far - by jumping on stage wearing little more than an Australian flag and a smile.
The streaker interrupted the mid-show performance by 2016 Eurovision victor Jamala, and managed to flash his backside to the world before a burly security guard wrestled him off stage.
The invasion was commented on by UK presenter Graham Norton, who apologised for the nudity, before suggesting that viewers get "back to Jamala".
