Lee [R] has written just one novel

Lee, 79, stopped giving interviews after she won the Pulitzer Prize for her 1960 coming-of-age book, exploring racial prejudice in the American south.

The writer appeared in person to receive an award from the Los Angeles public library.

She was invited by Veronique Peck, the widow of actor Gregory Peck.

He won an Oscar for his starring role as lawyer Atticus Finch in the 1962 film version of the book and became a lifelong friend of Ms Lee.

The film's co-star Brock Peters, who played the black man falsely accused of rape, presented the award to her.

After receiving the award, Lee said: "I'll say it again. Thank you all from the bottom of my heart."

Mrs Peck said Lee was "like a national treasure", adding: "She's someone who has made a difference with this book.

"All the kids in the United States read this book and see the film in the seventh and eighth grades and write papers and essays.

"My husband used to get thousands and thousands of letters from teachers who would send them to him."