Real name: Karl Johan Schuster

Swedish music producer, songwriter and musician, born February 1, 1985.

He started out as a drummer in local indierock bands in Karlshamn, before joining the hardcore/metal scene as a vocalist for the bands Skörda and Blinded Colony. Following the release of Bedtime Prayers though Pivotal Rockordings, and extensive touring of Europe with Blinded Colony, Johan left the band in August 2007 to focus on songwriting.

Together with Max Martin, he has written hit singles such as "So What" and "Raise Your Glass" with Pink, "If U Seek Amy" and "3" for Britney Spears, "DJ Got Us Fallin' in Love" for Usher and "Whataya Want from Me" for Adam Lambert.

Johan currently uses the name Shellback for his songwriting and production credits and is since 2007 part of Max Martin's Maratone production studio.