harper lee Harper Lee has died at 89 years old. Chip Somodevilla/Getty

It has just been announced that Harper Lee - the private author who wrote the classic novel "To Kill A Mockingbird" as well as the controversial prequel "Go Set a Watchman" - has died.

She was 89 years old.

Born Nelle Harper Lee, she became famous after "To Kill A Mockingbird" became an immediate best seller after it was published in 1960. Not one year later, it would win the Pulitzer Prize for fiction and go on to become one of the most-read books in schools across America.

But if it weren't for a 1950s Christmas gift, Lee might never have written "To Kill A Mockingbird" in the first place.

Back in 1956, Lee was a ticket agent for British Overseas Airways Corporation. Like most struggling writers, she was having trouble balancing her job and finding time to write.

She told this to her New York City friends, Michael and Joy Brown (who were also friends of Truman Capote - quite the literary circle).

Michael was a successful "industrial musical writer" whom American corporations hired to create performances to inspire their workers. His clients ranged from DuPont to JC Penney, and he was raking in the money for songs like "The Wonderful World of Chemistry," according to his New York Times obituary last year.

Harper Lee Young Harper Lee when she won the Pulitzer Prize in 1961. AP Photo

So in 1956, the Browns' gave Lee the best Christmas present of all: an entire year's salary so she could take time to write whatever she wanted.

"There was an envelope on the tree, addressed to me. I opened it and read: 'You have one year off from your job to write whatever you please. Merry Christmas,'" she wrote in McCall's magazine in 1961.

"They assured me that it was not some sort of joke," Lee wrote. "They'd had a good year, they said. They'd saved some money and thought it was high time they did something about me."

Lee took that time to write "To Kill A Mockingbird," which has since sold over 30 million copies worldwide and is still read in classrooms around the country.