Reese Witherspoon has an unusual keepsake she treasures - a heartfelt letter from her favourite English teacher.

The LEGALLY BLONDE star's high school teacher MARGARET RENKEL was the woman who turned the Hollywood beauty into a bookworm, and Witherspoon has often written to her expressing gratitude.

But one reply from the teacher left the actress in floods of tears.

She recalls, "I had this wonderful English teacher when I was a junior in high school, who made me love books and love the analysis of literature.

"I love her and I write her letters and one of my proudest moments was when she wrote me a letter telling me she was proud of me. It was really sweet.

"I cried about it for days. I carried it in my purse. I went to an all-girls school and (she wrote) just how many young women she thought I was inspiring and that it was just so great to be a woman of dignity and respect, and having any part of it just made her feel really great."