La moutarde me monte au nez

 

British actress Jane Birkin appeared in a cowgirl / sheriff outfit in the French movie I'M LOOSING MY TEMPER from 1974, including a blue jean vest. Found in the WWW, displayed not chronological.

Taxi

 

American actress Marilu Henner was one of the main actresses in the New York based TV-series TAXI from 1978. In the second episode of the first season, One-Punch Banta, Marilu wears a blue jean vest. I'm sorry, but at the moment the episode seems only to be available in a very low resoluted version, so the vidcaps are not really satisfying.

There is also another main actor in TAXI wearing a denim vest: Judd Hirsch, better known as the father of Jeff Goldblum in Independence Day. 

Le Magnifique

 

Beautiful French actress Jacqueline Bisset wears an early denim on denim outfit with jeans skirt, blouse and denim vest in the 1973 French movie THE MAGNIFIQUE.