Type 2 diabetes.
Hanks, looking slimmer and trimmer than he has in years, appeared on "Late Show With David Letterman" on Monday to promote his new movie, "Captain Phillips," but he wasted no time in getting to his major personal announcement.
"I went to the doctor and he said, 'You know those high blood-sugar numbers you've been dealing with since you were 36? Well, you've graduated! You've got Type 2 diabetes, young man.'"
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The audience did not react well, but Hanks was quick to put them at ease.
"It's controllable," he said, but then added, "Something's gonna kill us all, Dave."
The good news is that the diabetes is controllable; the bad news is that it would require Hanks to pull off a level of actorly weight control to rival Christian Bale and Robert De Niro.
"My doctor said, 'Look, if you can weigh as much as you weighed in high school, you'll essentially be completely healthy. You will not have Type 2 diabetes,'" Hanks said. "I said to her, 'Well, I'm going to have Type 2 diabetes, because there's no way I can weigh as much as I did in high school.'"
Hanks' high school weight: 96 pounds. "Most of it was that big, wide afro," Hanks said.