I don't think she knew how to process it," Keough says of her mother coping with her father's death, which occurred in August 1977 when Lisa Marie was 9.

Lisa Marie was 9 years old and living at Graceland with her famous father when he died of a heart attack at age 42.

Oprah Winfrey is sitting down with Riley Keough in a brand-new special to discuss the legacy of her famous family, including late grandfather Elvis Presley and her late mother Lisa Marie Presley. Nearly two years after Lisa Marie's death,