United Kingdom, Sept. 4 -- George Clooney has opened up about the pain of losing his sister Adelia 'Ada' Zeidler last year.

The Hollywood actor, 64, was left devastated when his elder sibling died in December at the age of 65 following a battle with cancer and he's now revealed he was holding her hand when she passed away and the tragedy forced him to re-evaluate his life.

Speaking at a masterclass event at the Venice Film Festival, in Italy, George said of his loss: "She died very quickly, and I was with her when she died. And there was this feeling, being with her, holding her hand when she died, understanding how brief all of this is.

"It was minutes ago that she and I were little kids together; Minutes ago we were holding hands as ...