Karl Johan Schuster, known professionally as Shellback, is a Swedish record producer, songwriter and multi-instrumentalist. 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 has won four Grammy Awards.

Karlshamn is a locality and the seat of Karlshamn Municipality in Blekinge County, Sweden. It had 13,576 inhabitants in 2015, out of 31,846 in the municipality.