Klemens Hannigan was born in Brussels, Belgium, in 1994. At the age of five he moved with his parents to Iceland, but in 2010 moved back and lived there for 3 more years. He went to the same school with Einar Stefánsson and to the same college with his cousin Matthías Haraldsson. Later, in 2015, they formed a band called Hatari, and in 2019 they perfomed at the Eurovision song contest.