Jane March was naked throughout most of her movie debut. She was 18 at the time, and a totally fresh face. [direct link, alternate link]
This film is a large cut above the typical soft-core sex film, in that it was directed by the esteemed Jean-Jacques Annaud, director of such acclaimed films as Enemy at the Gates, Seven Years in Tibet and The Name of the Rose. The Lover succeeds in may ways. The cinematography is spectacular, and the sex either is real or seems real, choices which are indistinguishable to us. (My review)