After battling a rare autoimmune disorder, Ashton Kutcher says he's "lucky to be alive."

Ashton Kutcher is contemplating his personal battle with a rare health condition.

On August 8, Access Hollywood shared an exclusive sneak peek of the actor's upcoming episode of Running Wild with Bear Grylls

n which he publicly revealed his diagnosis for the first time.

 "Like two years ago, I had this weird, super rare form of vasculitis that knocked out my vision

knocked out my hearing, knocked out like all my equilibrium," he said of the condition,

which causes inflammation of the blood vessels. "It took me about a year to rebuild it all."