Carlsson frequently collaborates with writers Chris Braide and Desmond Child. They have written many American hit songs including “Invisible” by Clay Aiken and “Waking Up In Vegas” by Katy Perry. Carlsson was a judge on X Factor Sweden in 2012. He was part of the Jury for the Swedish edition of Idol. Some of Carlsson’s other notable writing credits include “I Want It That Way” by the Backstreet Boys and “Bye Bye Bye” and “It’s Gonna Be Me” by NSYNC. He has also written for Britney Spears, Westlife, Celine Dion, Def Leppard, LeAnn Rimes, Bon Jovi, Hilary Duff, Lindsay Lohan, Diana DeGarmo, Carrie Underwood, Jesse McCartney, Paul Stanley, Europe, Tokio Hotel and Kerli, Play, Ricky Martin, and Jedward.