"To Kill a Mockingbird" author Harper Lee has died at the age of 89.

HarperCollins confirmed that Lee died peacefully Thursday night.

The author was known for most of her life for her one novel, "To Kill a Mockingbird," which dealt with racial tensions in a small Southern town as seen through the eyes of its young female narrator, Scout. Lee won the Pulitzer Prize in 1961 for "To Kill a Mockingbird," which has become a classic in American literature. The film adaptation, considered a classic in its own right, was released in 1962.

Born in Monroeville, Lee lived in New York City for many years before returning to her hometown later in life.

Lee made headlines when her second novel, "Go Set a Watchman," was published on July 14, 2015. Originally written in the mid-1950s,  Lee submitted "Go Set a Watchman" to her publishers before "To Kill a Mockingbird." The manuscript was thought to be lost before it was rediscovered in 2014. Set two decades after "To Kill a Mockingbird," the book was met with mixed reviews.

In 2007, Lee was awarded the Presidential Medal of Freedom.

Fans took to social media to pay respects.