Her talent was discovered in 1979 by Swedish musician and TV host
Lasse Holm. She was produced by
Bert Karlsson's label
Mariann Grammofon AB. In 1980, she joined Lasse's group
Chips. Chips participated in the
Eurovision Song Contest 1982 with the song "Dag efter dag" ("Day After Day"), and reached 8th place.
Andreassen is active in many musical genres such as
musicals. She is mostly famous from
Eurovision Song Contest 1985 when she and
Hanne Krogh participated as
Bobbysocks with the song "
La det swinge", and won.
Andreassen has sung in various genres such as
rock and in
musicals. She plays three
contrabass. She has also been a revue and musical artist.
"Bettan" has a record as the woman with the most participations in the
Eurovision Song Contest, tied with
Lys Assia, Sue of
Peter, Sue & Marc, and
Valentina Monetta. She has participated four times, three times in duets (with Kikki Danielsson in 1982, Hanne Krogh in 1985, and
Jan Werner Danielsen in 1994) and once on her own (in 1996).