The actor is one of the few stars who know how the series will end and he admits the show's creators have outdone themselves.
He tells Entertainment Weekly magazine, "I found the finale incredibly powerful. So much so that after I finished reading what I received, I had to sit for a few minutes after I closed the last page, just to reflect on it.
"It's big and it's significant. It's very emotionally resonant. I was satisfied by it. At its heart, Lost is a story about characters. There is a lot of sci-fi to it, but it's all very human. The stakes are very real. It's relatable. I really had to sit there in silence for a while because it meant a lot to me."
The cast will shoot the final scenes in the next two weeks and the finale will air in the U.S. in May (10).