Ashton Kutcher says he's 'lucky to be alive' after battle with rare autoimmune disease

LOS ANGELES -- Actor and producer Ashton Kutcher says he is "lucky to be alive" after a private battle with a rare autoimmune disorder.

The health scare took place about two years ago.

Kutcher made the revelation on the National Geographic series "Running Wild with Bear Grylls."

The actor says a rare form of vasculitis took away his sight, hearing and some of his motor control. Kutcher told Grylls it took him about a year to build himself back up.

The episode of "Running Wild" aired Aug. 8 on National Geographic.

The Walt Disney Company is the parent company of National Geographic Partners and this ABC station.