The 26-year-old American superstar, famous for hits including We Can’t Stop, Wrecking Ball and Party In The U.S.A., took a student cap (studenterhue), worn by newly-graduated upper secondary school students, from a member of the crowd and briefly wore it during her set.

The owner of the cap appeared delighted to have been able to offer up his headgear.

Photo: Helle Arensbak / Ritzau Scanpix

Student caps are traditionally worn every year by graduating high school classes all over Denmark. The caps are normally marked inside by wearers according to custom as they celebrate their achievements in exams – and during subsequent celebrations.

READ ALSO: Danish students and caps: What's all the noise about?

Although these traditions vary regionally, none are thought to involve lending the studenterhue to a world-famous singer.

But Odense graduates may have just been set the toughest student cap challenge of all, should anyone wish to emulate Saturday’s moment on the Tinderbox stage.

Although Cyrus’ music is not generally known for its political message, she thanked the crowd at the Danish festival with a speech in which she addressed the political situation in the United States, while praising what she had seen of life in Denmark, Soundvenue writes.

“There is no planet B,” she said to an enthusiastic response from the audience.

In its review, Soundvenue said Cyrus' set at the festival was “dubious” and “a little too short”, but commended her “presence and energetic performance.”