Originally comprised of vocalists Jenny Berggren and Malin "Linn" Berggren, and keyboardists Jonas "Joker" Berggren and Ulf "Buddah" Ekberg, the Swedish quartet Ace of Base became a phenomenally popular international act with their 1993 debut album, The Sign, one of the highest-selling debuts of all time. Ace of Base's simple, melodic Euro-disco was equally popular on radio and in the clubs, earning the quartet three U.S. Top Ten singles -- "All That She Wants," "Don't Turn Around," and "The Sign," which spent six weeks at number one. At the height of their popularity, they were the third most successful Swedish band after ABBA and Roxette.