Stefán Karl Stefánsson was an Icelandic actor and singer. He began his professional career at the age of 19, working as a puppeteer for television. Stefánsson played Robbie Rotten in the children's television show LazyTown and appeared in the films Regina with Baltasar Kormákur and Polite People. His music contributions include his popular single Aleinn um jólin with Björgvin Helgi Halldórsson. He returned to Iceland in 2016 to receive treatment for cholangiocarcinoma and died in 2018.