TO GO WITH AFP STORY BY CAMILLE BAS-WOHLERT: Bjorn Kristian Ulvaeus, a former member of the Swedish music group ABBA, is pictured during an interview on April 29, 2013 at the Swedish Music Hall of Fame where 'ABBA The Museum' is set to open on May 7 in Stockholm. ABBA's collected works will be showcased in a contemporary, interactive setting at Swedish Hall of Fame, a new exhibit venue located at Djurgarden, Stockholm. AFP PHOTO/JONATHAN NACKSTRAND

TO GO WITH AFP STORY BY CAMILLE BAS-WOHLERT: Bjorn Kristian Ulvaeus, a former member of the Swedish music group ABBA, is pictured in front of an ABBA placard on April 29, 2013 at the Swedish Music Hall of Fame where 'ABBA The Museum' is set to open on May 7 in Stockholm. ABBA's collected works will be showcased in a contemporary, interactive setting at Swedish Hall of Fame, a new exhibit venue located at Djurgarden, Stockholm. AFP PHOTO/JONATHAN NACKSTRAND

TO GO WITH AFP STORY BY CAMILLE BAS-WOHLERT: Bjorn Kristian Ulvaeus, a former member of the Swedish music group ABBA, is pictured in front of an ABBA placard on April 29, 2013 at the Swedish Music Hall of Fame where 'ABBA The Museum' is set to open on May 7 in Stockholm. ABBA's collected works will be showcased in a contemporary, interactive setting at Swedish Hall of Fame, a new exhibit venue located at Djurgarden, Stockholm. AFP PHOTO/JONATHAN NACKSTRAND