Teri Garr in One From the Heart (1982)
She never did a nude scene when she was young. She was already 36 or 37 when the above scene was lensed (she was always older than she looked), and it was the one and only time her breasts appeared on camera.
In theory, she did do a full rear nude scene in The Moonshine War (1970, when she was 25), but the camera was so far away that it could have been anyone. In fact, they could have used a man as her body double and you would not have been able to tell at that distance.
Teri turns 74 this year, and is currently battling MS.
There goes my day… That was damn depressing…