Swedish pop singer and television presenter who finished in fifth place in Idol 2005 and in first place in the inaugural season of Let's Dance. He hosted Allsång på Skansen from 2011 to 2013. He co-hosted the Eurovision Song Contest 2016 following his win the previous year with his song "Heroes."
He studied music in high school, was part of his school's choir and played a brother in a rendition of Joseph and the Amazing Technicolor Dreamcoat.
He participated in Melodifestivalen in 2007, 2009 and 2015, winning the competition in 2015.
He was born to a professor named Birgitta Sahlén and surgeon Sven-Olof Zelmerlöw. He has a younger sister named Fanny. He and his girlfriend Ciara Janson announced they were expecting their first child together in December 2017.
He dated former A-Teens member Marie Serneholt from 2008 to 2011.