With the Hep Stars ' popularity diminishing , Lotta was brought in as a new member of the band , along with Benny 's songwriting colleague , Björn Ulvaeus . This constellation released two studio albums on their own record label Romance Records , '' Compromise '' and '' Tillsammans '' . The new line-up did n't last long however , with Benny and Björn setting their sights on international stardom with their fiancées , Anni-Frid Lyngstad and Agnetha Fältskog . Aiming to follow in ABBA 's victorious footsteps , Svenne and Lotta competed in the Swedish heats for the Eurovision Song Contest , Melodifestivalen 1975 , with the song " Bang-A-Boomerang " , but finished 3rd . The song however became their breakthrough in Scandinavia , and the duo became especially popular in Denmark . In the early 1980s they even took the unusual step of recording a Danish language version of their Swedish hit " När Dagen Försvinner " ( a cover of Alan Sorrenti 's " Tu sei l'unica donna per me " ) , retitled " Når Dagen Forsvinder "
Melodifestivalen 1975
Melodifestivalen 1975
Svenne and Lotta