Witherspoon, 34, was brought up in Nashville, Tennessee, and said her mother's lessons shaped the way she was brought up.
She said to UK newspaper Daily Mirror: 'I was always taught that good manners cost nothing - but are worth such a lot. My mother, Betty, even sent me to etiquette lessons.
'It was close to the old-fashioned English upbringing, where you learn where to place the knives and forks. I had that bred in to me, even though we lived in Nashville, Tennessee.
'I was taught to be polite in conversation, smile a lot and treat people with respect. Whenever I talk about what it means to be a girl from the American south, I always end up talking about guilt. We can't stand anyone not liking us!'