Kieran Culkin Calls Sister's Sudden Death 'Worst Thing That's Ever Happened' to His Family

Kieran Culkin is still mourning the death of his older sister Dakota over a decade after she was killed in a tragic traffic accident.

In an interview with The Hollywood Reporter published Wednesday, the Succession star said everyone in his family was "torn up inside" after the accident.

"That's the worst thing that's ever happened, and there's no sugarcoating that one," Kieran told the outlet. "Each one of us handled it very differently."

Dakota, affectionately known as "Cody," was killed in December 2008 after she was struck by a car while crossing Lincoln Boulevard in Marina del Rey, Calif., ABC News reported. She was 29.

Though nearly 13 years have passed since she died, Kieran said the tragedy still feels surreal. Knowing that his children — Kinsey, 2, and newborn Kieran Jr. — will never get to meet their aunt is especially difficult.

"I accepted at the time that this is going to be forever, and it's never going to be fine. It's always going to be devastating," the actor told THR of the grief. "I still weep about it out of nowhere. Something funny she did will pop in the head and make me laugh, and then I'm weeping.

"Sometimes it's knowing that she's not going to meet my kids and they don't get to have her, and it's hard to describe what she was like," he added.

According to the report, the season 3 premiere of HBO's Succession features a scene where Kieran's character mocks his on-screen sister Shiv, played by Sarah Snook, during an argument by saying "Dur-dur-dur-dur-durrr!" while making a silly face.

It's a card the actor said his late real-life sister used to play.

"That's hers," Culkin explained. "That's just Cody's move. You could never get one up on her because, even if she was wrong — 'Dur-dur-dur-dur-durrr!' — then she wins the argument. Cody is pretty Roman-y. It's as if Roman were portrayed by Darlene from Roseanne. Darlene Connor as Roman Roy."

To honor Cody, Kieran's brother Macaulay Culkin named his first child, son Dakota, after their late sister. The American Horror Story star and Brenda Song welcomed the baby boy in in April.

Season 3 of Succession premieres Oct. 17 on HBO.