According to the actor, 57, he had been dealing with high blood sugar numbers since he was 36, but recently his doctor told him, "You've graduated. You've got Type 2 diabetes, young man."
Hanks, who has a history of drastic weight fluctuation for roles, shared the news when David Letterman remarked that he looked slimmer. "My doctor said, 'Look, if you can weigh as much as you weighed in high school, you will essentially be completely healthy and not have Type 2 diabetes,'" Hanks said. "And I said to her, 'Well, I'm gonna have Type 2 diabetes.'"
Watch Hanks' reveal below.