Austin Butler Speaks Out After Lisa Marie Presley's 'Tragic' Death: 'My Heart Is Completely Shattered'

Austin Butler is honoring Lisa Marie Presley after her death at 54, just days after attending Golden Globe alongside her.

One of the last people to spend time with the star, Butler, 31, said Friday that his "heart is completely shattered" for her children and mother after "the tragic and unexpected loss of Lisa Marie."

"I am eternally grateful for the time I was lucky enough to be near her bright light and will forever cherish the quiet moments we shared," the actor said in a statement shared with PEOPLE.

"Her warmth, her love and her authenticity will always be remembered."

The actor stars as Elvis Presley in the Baz Luhrmann film Elvis, which was a nominee at the award show on Tuesday. Butler won best actor in a drama that night, and Lisa Marie was in the audience to cheer him on. In his acceptance speech, Butler thanked the Presley family "for opening your hearts, your memories, your home to me."

"Lisa Marie, Priscilla," he continued in his speech, "I love you forever."

On Thursday, Lisa Marie, the only child of rock legend Elvis, was rushed to the hospital, and died later that night. Her mother Priscilla Presley said in a statement to PEOPLE, "It is with a heavy heart that I must share the devastating news that my beautiful daughter Lisa Marie has left us."

Priscilla continued, "She was the most passionate strong and loving woman I have ever known. We ask for privacy as we try to deal with this profound loss. Thank you for the love and prayers. At this time there will be no further comment."

Lisa Marie was mom to daughter Riley Keough, 33, 14-year-old twins Harper and Finley, plus son Benjamin Keough, who died by suicide in July 2020.

At a party celebrating the Elvis film the weekend before the Golden Globes (on Sunday, Jan. 8, Elvis's birthday), Lisa Marie addressed the attendees and said her dad would be proud of the movie.

"I'm so overwhelmed by this film and the effect that it's had and what Baz has done, Austin's done. I'm so proud, and I know that my father would also be very proud. ... I'm overwhelmed with gratitude, so thank you," she said at the gathering.

In June, Butler told PEOPLE about the responsibility he felt to the Presley family in capturing Elvis's story for the big screen: "I can't even put into words how much it means to me because I felt so much responsibility to them the entire time. That's the thing that would shoot me out of bed in the morning every day [during production]. I had no idea how they were going to respond. I was fully ready for them maybe not to want to watch it or not to like it or anything."

He added, "I feel like I'm in a dream right now because they have been so warm and welcoming."

Warner Bros. Pictures, the studio behind Elvis, said in a statement, "We are deeply saddened by the passing of Lisa Marie Presley and send our condolences and sympathy to her children, family and people around the world who loved her. She was an invaluable partner and truly lovely person who we will remember as a devoted mother, beloved daughter and loving friend."