Jonas Petter Berggren, born on March 21, 1967, is a Swedish musician, singer-songwriter, and record producer, also known by his stage name "Joker." He is a founding member of the internationally successful pop group Ace of Base, which originally included his siblings Linn and Jenny Berggren, making him the only male member among the three siblings. Jonas began writing songs at the age of seven and has continued to contribute to Ace of Base's discography, as well as writing for other artists. Some of the most popular songs he has been involved in include "The Sign," "All That She Wants," and "Happy Nation." His work with Ace of Base has left a significant mark on the music industry, and he remains an influential figure in Swedish pop music.