George Clooney has shared a personal and poignant account of his sister Adelia "Ada" Zeidler's final moments, who died of cancer at the age of 65 last December.

During a masterclass at the Venice Film Festival this week, Clooney recalled being with his sister when she passed away. "She died very quickly, and I was with her when she died," he said, as reported by Variety. "And there was this feeling, being with her, holding her hand when she died, understanding how brief all of this is."

The actor, who was honored with the Golden Lion for Lifetime Achievement at the festival, reflected on the swift passage of time. "It was minutes ago that she and I were little kids together; minutes ago we were holding hands as little kids," he stated. "Time goes fast. All of this. And so we have to find nothing but joy."

Although Zeidler lived a life away from the spotlight, she was seen with her famous brother in Venice in 2014 during his wedding to Amal Clooney.

Following his sister's death, Clooney had previously described her as his "hero" in a statement.