Her measurements at the age of 18 were given as 32-22-34 in 1963's "Movie Life Yearbook."
Her original American name was Martha, but upon embarking on an acting career she changed it to the more European-sounding "Marta".
In 1964 she auditioned for the role of Liesl Von Trapp in The Sound of Music (1965).
She occasionally does nostalgia shows with Angela Cartwright.
She was born out of wedlock in Norway to a Finnish mother and a German soldier -- the German army was occupying Norway at the time -- who was later killed in combat. She was left in an Oslo orphanage at the age of two months. In 1949 she was adopted by an American couple and grew up in the United States.