I saw it on tv in the late 70s/early 80s so it was probably set in the late 60s/early 70s.
It was a light and breezy romantic comedy. The main female character shoplifted clothes by wearing loads of layers of them. (She may also have had a large coat with pockets to put stuff but am not sure if I am remembering another film).
She gets married in the end but wears a grooms outfit; either a dark suit or dinner jacket. I remember thinking it was so rebellious and glamorous (I was 13!)
Every few years I remember it so I look in books, or google or post messages on boards am on. I have a feeling I may have asked here a few years ago but couldn't find it when I searched.
Any help will be great.