Pop, electropop, dance-pop, pop rock, melodic death metal
Songwriter, record producer, musician
Guitar, drums, bass, keyboards, vocals
Karl Johan Schuster (born February 1, 1985), known professionally as Shellback, is a Swedish songwriter, record producer and musician. Shellback was listed as the No. 1 producer of 2012 on Billboard magazine's year end chart, and he also topped the list of their "Top 10 Songwriters Airplay Chart" the same year. He regularly collaborates with songwriter Max Martin, and together they have produced, written and/or co-written songs for P!nk, Taylor Swift, Adam Lambert, Britney Spears, Usher, Avril Lavigne, Ariana Grande, Maroon 5, and Adele. Shellback has collaborated with fellow producer Benny Blanco on numerous occasions and has produced several songs by himself as well.