3:57 PM PT -- Lisa's manager, Roger Widynowski, tells TMZ ... "She is completely heartbroken, inconsolable and beyond devastated but trying to stay strong for her 11 year old twins and her oldest daughter Riley. She adored that boy. He was the love of her life."
Law enforcement sources tell us Ben appears to have died Sunday in Calabasas from a self-inflicted gunshot wound.
Not much is known about him other than the fact that he's got a super-famous family. He's the son of Lisa and musician Danny Keough -- and his sister is actress Riley Keough, who's been in a number of indie and horror films over the years, including 2019's "The Lodge."
Of course ... his grandparents are Elvis and Priscilla Presley.
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Ben has kept a low profile throughout the years, but the one thing he's well-known for is looking almost identical to his famous grandfather, The King himself.
Lisa addressed the similarity, saying ... "Ben does look so much like Elvis. He was at the Opry and was the quiet storm behind the stage." She added, "Everybody turned around and looked when he was over there. Everybody was grabbing him for a photo because it is just uncanny." She even wrote a song about Ben called "Storm and Grace." Storm's his middle name.
He was also a musician ... he even struck a record deal back in 2009 worth $5 million. He's got a couple acting credits under his name, but aside from that, not much else is known about him publicly. He has few social media accounts.
One of the last times he was seen out with the family was during Elvis' 40-year death anniversary during a vigil at Graceland.
Benjamin was just 27.
Originally Published -- 3:26 PM PT