One of the biggest mysteries of “Lost” — the Smoke Monster — will be unveiled on the popular TV drama, and soon.

Actor Daniel Dae Kim, who plays Jin, said in an interview that the origin and nature of the malevolent dark cloud will be disclosed and viewers will even get a glimpse of its lair.

Turns out the monster is as “old as the island” that’s been home to the Oceanic jet-crash survivors and their foes.

Kim also cautioned against expectations that his character, Jin, will reunite with his wife, Sun (Yunjin Kim), even though Jin survived a freighter explosion and Sun returns to the island after escaping it.

Those events don’t mean “they’re particularly in the same place or chronologically in the same time,” Kim said.

As for the atomic bomb that showed up in the “Jughead” episode, he said the show’s producers rarely give something such prominence unless it counts in the island’s mythology.

“That’s a huge red herring if it’s a red herring,” Kim said, suggesting the bomb could help resolve plot points as the series ends in 2010.

Perhaps the time-traveling that’s popped up this season might be one of those.