Lisa Marie Presley died of a "broken heart", unable to get over her son's suicide, her daughter has revealed.

Riley Keough has broken her silence following her mother's death in January last year. Although the Los Angeles County medical examiner's office ruled the only child of rock 'n' roll legend Elvis died of a bowel obstruction that caused a cardiac arrest, the actress says it was grief that led to her death.

"My mom tried her best to find strength for me and my younger sisters after Ben died, but we knew how much pain she was in," Riley, 35, said.

"My mom physically died from the after-effects of her surgery, but we all knew she died of a broken heart." The obstruction detected by the examiner's office was a result of adhesions caused by weight-loss surgery she underwent several years ago.

Riley Keough and mother Lisa Marie Presley (
Image:
Getty Images for ELLE)

Before her death, Lisa Marie, who was 54 when she died, was vocal about her grief, saying she would never "move on" from her son Benjamin's 2020 death. He died at age 27 from a self-inflicted gunshot wound.

In her haunting final Instagram message, posted in August 2022, Lisa Marie shared an essay she had written about her loss.

She explained: "Grief does not stop or go away in any sense, a year, or years after the loss. Grief is something you will have to carry with you for the rest of your life, in spite of what certain people or our culture wants us to believe. You do not 'get over it,' you do not 'move on,' period. My and my three daughters' lives as we knew it were completely detonated and destroyed by his death. We live in this every. Single. Day."

Next month, Lisa Marie's posthumous memoir 'From Here to the Great Unknown' is set for release. Riley said of her mother's book: "I hope that in extraordinary circumstances, people relate to a very human experience of love, heartbreak, loss, addiction, and family. "[My mom] wanted to write a book in the hopes that someone could read her story and relate to her, to know that they're not alone in the world."

Lisa Marie Presley underwent weight-loss surgery before her death (
Image:
Getty Images for Icelandic Glacial)

She added: "Her hope with this book was just human connection. So that's mine."

Lisa Marie was buried on January 22 last year at Graceland the Memphis home where she lived with her father as a child that has become a museum, tourist attraction and shrine for Elvis fans. She left behind three daughters, Riley Keough and 16-year-old twins Harper and Finley Lockwood.

In the immediate aftermath of Lisa Marie's death, it appeared that a major legal fight would ensue over Elvis's estate.

Four days after her funeral, her mother, Pricilla Presley, filed legal documents disputing a 2016 amendment to Lisa Marie's living trust. The papers had removed Elvis’s ex-wife, 79, and a former business manager as trustees and replaced them with her two eldest children.

But Priscilla and Keough, who is now acting as sole trustee, agreed to a settlement in May last year.