TULSA, Oklahoma - A memorial service is being planned for Tulsa native and best-selling author Billie Letts who died Saturday, August 2, 2014, in a local hospital.

"There has been a large outpouring of condolences from many friends and fans around the country," said publicist and friend Arlene Johnson.

"Her passing has come as a great shock not only to her family and close friends, but to her thousands of fans."

Letts, 76, died after a brief illness.

"She entered St. Francis Hospital last Monday and died early Saturday morning. All of her friends and family are still in shock at how quickly this happened," Johnson said.

Letts is best known for her internationally acclaimed novels: "Where The Heart Is," "The Honk And Holler Opening Soon," "Shoot The Moon" and the recent "Made In The U.S.A."

"Where The Heart Is" was an Oprah Winfrey Book Club selection that reached No. 1 on the New York Times paperback bestseller list. It was made into a movie starring Natalie Portman and Ashley Judd, released by 20th Century Fox in 2000.

She published her first novel at age 54. Letts was also a retired English and creative writing professor from Southeastern Oklahoma State University in Durant.

She is survived by three sons: Dana, Shawn and Tracy. Tracy Letts is a Pulitzer-prize winning playwright whose Broadway play, "August: Osage County," was made into a movie filmed in Oklahoma. It was based on Letts' dysfunctional family.

"The woman who plays the mother is based on my mother. And Barbara, the older sister who takes over, is based on me," she told News On 6 anchor Terry Hood in an interview last year.

She fully supported her son's use of her family history of her mother's drug addiction, Letts said during the interview.

Dennis Letts, Billie's husband, played the role of the family patriarch on Broadway. He died of cancer in 2008.

Johnson said the date of Letts' memorial service is still pending but will be planned by the family in the coming weeks.