Lisa Marie Presley's son Benjamin Keough dies at 27

Left-right: Priscilla Presley, Lisa Marie Presley and Benjamin Keough pictured in 2010

Elvis Presley's only grandson died on Sunday, his mother Lisa Marie Presley's manager has confirmed.

Benjamin Keough was 27, but manager Roger Widynowski gave no further details about his death.

He said Lisa Marie, 52, was "heartbroken, inconsolable and beyond devastated".

"She adored that boy. He was the love of her life," Widynowski said, adding that she was "trying to stay strong" for her three daughters.

The Los Angeles County coroner's office confirmed that the death of a person of his name and age was under investigation, but there was no other immediate information on the circumstances.

He was the younger of the two children Lisa Marie Presley had with her first husband, musician Danny Keough, before their divorce in 1994. The other is actress Riley Keough, 31.

Lisa Marie had previously described Keough's resemblance to her famous father as "just uncanny." Rock 'n' roll legend Elvis Presley died in 1977 aged 42.

Lisa Marie also has twin 11-year-old daughters with her fourth husband, musician and producer Michael Lockwood, who she wed in 2006 after brief marriages to pop star Michael Jackson and actor Nicolas Cage.

Her close relationship with her son, whose middle name was Storm, apparently inspired the title track on her third album, Storm & Grace, released in 2012.